Test head manipulator

ABSTRACT

A test head manipulator system comprising a base structure, a main arm unit configured to support a test head and to be moved relative to the base structure, an actuator having a range of motion of L, and an enhancement mechanism positioned between the main arm unit and the actuator and configured such that movement of the actuator a first distance causes the main arm unit to move a second distance that is greater than the first distance. Additionally, a fluid control system for controlling a test head manipulator system. The pneumatic control system includes a regulator configured to controllably provide an output pressure to the main fluid actuator, and a second fluidly controlled actuator configured to adjust the regulator to modify the output pressure provided to the main fluid actuator. The second actuator is configured to be positively positioned in at least four operating modes with each operating mode causing the regulator to provide a different output pressure to the main fluid actuator.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent ApplicationSer. No. 60/903,015, filed Feb. 27, 2007; U.S. Provisional PatentApplication Ser. No. 60/894,515, filed Mar. 13, 2007; U.S. ProvisionalPatent Application Ser. No. 60/955,515, filed Aug. 13, 2007; and PCTInternational Application No. PCT/US2008/002134, filed Feb. 19, 2008,which are incorporated fully herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to systems for positioning andmanipulating loads, and more particularly, to systems for positioningand manipulating test heads.

Test heads are often utilized in the testing of integrated circuits. Inorder to use a test head to test integrated circuits, the test head istypically “docked” to a piece of peripheral equipment such as a proberor a device handler (hereinafter “peripheral”). A test head manipulatoris typically used to position and manipulate the test head during thedocking operation.

In docking a test head to a peripheral, it is desirable that the testhead be moveable in a number of directions (i.e., that the test headhave a number of degrees of freedom). Further, it is, also desirable tohave the test head be compliantly moveable with respect to variousdegrees of freedom (i.e., the test head is substantially weightless ormay be moved with a relatively small amount of externally applied forcewith respect to each of the degrees of freedom).

If a test head can move (in conjunction with the test head manipulator)along and rotate about each of X-axis, Y-axis, and Z-axis, themanipulator is said to provide at least six (6) degrees of freedom. If atest head can be moved compliantly, both linearly and rotationally, withrespect to its own axes then the test head is said to be compliant withsix (6) degrees of freedom.

Because test heads are typically very expensive, it is often desirableto use the same test head to dock with various different peripherals.For example, the same test head may be used to dock in a horizontalplane with a device handler (e.g., a test head may dock with a devicehandler from below the device handler) and a prober (e.g., a test headmay dock with a prober from above the prober). In order to dock withvarious different types of peripherals, a test head manipulatordesirably has a long vertical stroke (e.g., a long vertical range ofmotion). However, because of size constraints on test heads and theassociated manipulators, this is not always practical. Additionally,certain test head manipulator systems utilize pneumatic cylinders toposition and manipulate test heads in the vertical direction. In such adesign, the vertical stroke provided by the test head manipulator islimited by the stroke of the pneumatic cylinder arrangement. Often, withlarger test heads, the stroke of a pneumatic cylinder arrangement may beinadequate to provide a vertical range of motion adequate for docking atest head with the different types of peripherals.

As provided above, in systems for the docking of a test head, it issometimes desirable to provide complaint motion in each of the testhead's six (6) degrees of freedom. This means that during docking, atest head manipulator desirably balances the test head in asubstantially weightless condition in each of the these six (6) degreesof freedom such that an operator can move the test head manually in eachof the directions with relatively little force. However, as test headshave become larger and heavier, the physical force required to manuallymanipulate the test head in certain directions (even in a compliantstate) may be difficult if not impossible for certain operators toprovide.

As such, it would be desirable to provide a test head positioning andmanipulation system addressing the above recited deficiencies.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides, a test head manipulatorsystem comprising a base structure, a main arm unit configured tosupport a test head and to be moved along a first axis relative to thebase structure, an actuator having a range of motion of L along an axisparallel to the first axis, and an enhancement mechanism positionedbetween the main arm unit and the actuator and configured such thatmovement of the actuator a first distance causes the main arm unit tomove along the first axis a second distance that is greater than thefirst distance.

In another aspect of the invention, the enhancement mechanism includes alift carriage which is associated with and moves with the actuator.

In yet another aspect of the invention, the enhancement mechanismfurther includes a strap which is looped about the lift carriage andwhich has a first end secured relative to the base structure and asecond end secured relative to the main arm unit.

In an alternative aspect, the present invention provides a fluid controlsystem for controlling a test head manipulator system which includes amain fluid actuator configured to vertically position a test headrelative to a base structure. The fluid control system includes aregulator configured to controllably provide an amount of fluid to themain fluid actuator, and a second fluidly controlled actuator configuredto adjust the regulator to modify the amount of fluid provided to themain fluid actuator. The second actuator is configured to be positivelypositioned in at least four operating modes with each operating modecausing the regulator to provide a different amount of fluid to the mainfluid actuator.

In another aspect of the invention, the second actuator is configured tobe positively positioned in a fifth operating mode which is a neutralmode.

In yet another aspect of the invention, the fluid control system furthercomprises a fluidly actuated safety lock configured to lock the verticalposition of the test head relative to the base structure if a fluidpressure in the main fluid actuator is below a threshold value.

In still yet another aspect of the invention, the fluid control systemfurther comprises a fluid rate control including at least one flowcontrol valve which is fluidly actuable between an open position andclosed position to increase or decrease, respectively, a rate of fluidflow to the main fluid actuator.

In yet another aspect, the present invention provides a fluid controlsystem for controlling a test head manipulator system which includes amain fluid actuator configured to vertically position a test headrelative to a base structure. The fluid control system includes aregulator configured to controllably provide an output pressure to themain fluid actuator at a first given rate along a first flow path. Asupplemental flow path extends between the regulator and the main fluidactuator. A supplemental valve is positioned along the supplemental flowpath and has a non-actuated, closed position. A controller is configuredto determine a vertical extension of the main fluid actuator and actuatethe supplemental valve when, the main fluid actuator is verticallyextended within a given range.

In still another aspect, the present invention provides a test headmanipulator system comprising a coupling unit configured to support atest head for rotation about a given axis. A rotation unit is configuredto controllably provide a rotational output. A drive belt extendsbetween the rotation unit and the coupling unit and is configured totransmit the rotational output to the coupling unit. At least one idleris biased into engagement with the drive belt and moveable over a givenpath such that when an external force is applied to the coupling unit,the idler maintains a desired tension on the drive belt.

In yet another aspect, the present invention provides, a test headmanipulator system comprising a base structure with a linear actuatorassembly. The linear actuator assembly comprises a fluid cylinderconnected at one end to the carriage, a brake shoe connected to a pistonrod extending from an opposite end of the fluid cylinder and at leastone ramp block defining a ramped slot, the at least one ramp blockconnected to the base plate for linear motion therealong. A pin memberextends from the brake shoe and is received in the ramped slot such thatmovement of the cylinder causes the pin member to move along the rampedslot and thereby move the brake shoe into and out of engagement with thebase plate.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is isometric view of an exemplary manipulator system inaccordance with a first embodiment of the present invention.

FIG. 1B is a partially exploded view of the manipulator system of FIG.1A.

FIGS. 2A, 2B and 2C are isometric views of the manipulator system ofFIG. 1A with the test head manipulated to different positions toillustrate an exemplary range of motion.

FIG. 3 is an isometric view illustrating an exemplary embodiment of theroll gear box with an exemplary cradle attached thereto.

FIGS. 4 and 5 are front and rear isometric views, respectively, of theroll gear box of FIG. 3.

FIG. 6 is an exploded isometric view of the roll gear box of FIG. 3.

FIG. 7 is a schematic drawing illustrating the roll compliance assemblyof the roll gear box of FIG. 3.

FIG. 8 is an isometric view of an exemplary compliance unit of the rollgear box of FIG. 3.

FIG. 9 is an isometric view similar to FIG. 8 shown in partial section.

FIG. 10 is a partially exploded isometric view of the idler assembly ofthe compliance unit of FIG. 8.

FIG. 11 is an isometric view of a shaft of the compliance unit of FIG.8.

FIG. 12 is an isometric view of the idler of the compliance unit of FIG.8.

FIG. 13 is an isometric view of the idler assembly of the complianceunit of FIG. 8.

FIG. 14A is an exploded isometric view of a roll gear box of alternativeexemplary embodiment of the invention.

FIG. 14B is an expanded view of the compliance unit of FIG. 14A.

FIG. 15 is an exploded isometric view of a roll gear box of anotheralternative exemplary embodiment of the invention.

FIG. 16A is a perspective view of the base unit of the manipulatorsystem of FIG. 1A.

FIG. 16B is a partially exploded view of the base unit FIG. 16A.

FIG. 17 is a perspective view of an alternate exemplary base unit of thepresent invention.

FIG. 18 is a partially exploded view of the base unit of FIG. 17.

FIG. 19 is a bottom perspective view of an exemplary carriage of thepresent embodiment.

FIG. 20 is an exploded isometric view of an exemplary linear actuatorassembly of the present embodiment.

FIG. 21 is a top plan view of the base unit of FIG. 17, with supportsand the like removed for clarity, with the carriage and linear actuatorin an initial position.

FIG. 22 is a cross-sectional view along the line 22-22 in FIG. 21.

FIG. 22A is an expanded view as indicated by the rectangle 22A in FIG.22.

FIG. 23 is an end view along the line 23-23 in FIG. 21.

FIG. 23A is an expanded view as indicated by the circle 23A in FIG. 23.

FIG. 24 is a top plan view similar to FIG. 21, with the carriage andlinear actuator in an initiate extension position.

FIG. 25 is a cross-sectional view along the line 25-25 in FIG. 24.

FIG. 25A is an expanded view as indicated by the rectangle 25A in FIG.25.

FIG. 26 is an end view along the line 26-26 in FIG. 24.

FIG. 26A is an expanded view as indicated by the circle 26A in FIG. 26.

FIG. 27 is a top plan view similar to FIG. 21, with the carriage andlinear actuator in an extension position.

FIG. 28 is a cross-sectional view along the line 28-28 in FIG. 27.

FIG. 28A is an expanded view as indicated by the rectangle 28A in FIG.28.

FIG. 29 is an end view along the line 29-29 in FIG. 27.

FIG. 29A is an expanded view as indicated by the circle 29A in FIG. 29.

FIG. 30 is a top plan view similar to FIG. 21, with the carriage andlinear actuator in an completed extension position.

FIG. 31 is a cross-sectional view along the line 31-31 in FIG. 30.

FIG. 31A is an expanded view as indicated by the rectangle 31A in FIG.31.

FIG. 32 is an end view along the line 32-32 in FIG. 30.

FIG. 32A is an expanded view as indicated by the circle 32A in FIG. 32.

FIGS. 33A and 33B are right and left front perspective views,respectively, of the column assembly of the manipulator system of FIG.1A with the main arm assembly in a service position.

FIG. 33C is a right front perspective view of an alternative main armassembly.

FIG. 33D is a left rear perspective view of the main arm assembly ofFIG. 33C.

FIG. 33E is a cross-sectional view along the line 33E-33E in FIG. 33C.

FIGS. 34A, 34B and 34C are right-front, left-front and right-backperspective views, respectively, of the column body of the columnassembly of FIGS. 33A and 33B.

FIGS. 35A and 35B are right-front perspective views of the columnassembly showing the main arm assembly in its lowest and uppermostpositions, respectively.

FIGS. 36A, 36B, and 36C are cut-away perspective views of the columnassembly from the front right with the main arm in its lowermost,service and uppermost positions, respectively.

FIGS. 37A, 37B, and 37C are cut-away perspective views of the columnassembly from the rear left with the main arm in its lowermost, serviceand uppermost positions, respectively.

FIG. 38 is a perspective view of the main pneumatic cylinder assembly ofthe manipulator system of FIG. 1A.

FIG. 39 is a perspective view of the pulley lift carriage of themanipulator system of FIG. 1A.

FIG. 40 is a schematic free body diagram illustrating the forcesassociated with the pulley lift carriage.

FIGS. 41A and 41B are schematic diagrams illustrating exemplary verticalmotion of a load.

FIGS. 42A, 42B, and 42C are cut-away side views of the column assemblywith the main arm in its lowermost, service and uppermost positions,respectively.

FIGS. 43 and 44 are partial internal views of a pneumatics control unitin accordance with an exemplary embodiment of the present invention withthe unit in a neutral mode.

FIG. 45 is a partial internal view of the pneumatics control unitsimilar to FIG. 44 illustrating the blocking member in a non-blockingposition.

FIGS. 46 and 47 are partial internal views similar to FIGS. 43 and 44with the unit in an up mode; FIG. 46A showing a portion of the unit withthe manual mode assembly removed for clarity.

FIGS. 48 and 49 are partial internal views similar to FIGS. 43 and 44with the unit in an down mode; FIG. 48A showing a portion of the unitwith the manual mode assembly removed for clarity.

FIGS. 50 and 51 are partial internal views similar to FIGS. 43 and 44with the unit in a manual up mode; FIG. 50A showing a portion of theunit with the manual mode assembly removed for clarity.

FIGS. 52 and 53 are partial internal views similar to FIGS. 43 and 44with the unit in a manual down mode; FIG. 52A showing a portion of theunit with the manual mode assembly removed for clarity.

FIGS. 54 and 55 are front and back isometric views, respectively, of anexemplary remote control unit.

FIG. 56 is a view similar to FIG. 54 with a portion of the housingremoved.

FIG. 57 is a schematic diagram of an illustrative pneumatic controlsystem in accordance with an embodiment of the invention.

FIG. 58 is a schematic diagram of an illustrative pneumatic controlsystem in accordance with an alternative embodiment of the invention.

FIG. 59 is a schematic diagram of an illustrative pneumatic controlsystem in accordance with another alternative embodiment of theinvention.

FIG. 60 is an isometric view of a remote control unit of the pneumaticcontrol system of FIG. 59.

FIG. 61 is a view similar to FIG. 60 with the cover removed.

FIG. 62 is a front perspective view of a column assembly of analternative embodiment of the manipulator system of the presentinvention with the main arm assembly in the service position.

FIG. 63 is a right rear, cut-away perspective view of the columnassembly of FIG. 62.

FIG. 64 is a perspective view of an alternative embodiment of the pulleylift carriage.

FIG. 65 is a schematic free body diagram illustrating the forcesassociated with the pulley lift carriage of FIG. 64.

FIG. 66. is a left rear, cut-away perspective view of the column of FIG.62.

FIG. 67 is an expanded cut-away view of the interior of the columnassembly of FIG. 66.

FIG. 68 is an expanded cut-away view of the column assembly of FIG. 62with the main arm assembly in an upper position showing the interactionbetween the roller-actuated valve and the actuator plate.

DETAILED DESCRIPTION OF THE INVENTION

Preferred features of selected embodiments of this invention will now bedescribed with reference to the Figures. It will be appreciated that thespirit and scope of the invention is not limited to the embodimentsselected for illustration. Also, it should be noted that the drawingsare not rendered to any particular scale or proportion. It iscontemplated that any of the configurations and materials describedhereafter can be modified within the scope of this invention.

Test head manipulator system 10 which is a first embodiment of thepresent invention will be described with reference to FIGS. 1A-42C.Referring to FIGS. 1A and 1B, manipulator system 10 generally includescolumn unit 100, cradle 300, test head 490, main arm assembly 500, rollgear box 580, base unit 600, and controller 700. Not shown is themainframe cabinet of the automatic testing equipment (ATE) and thecable, which connects test head 490 to the mainframe cabinet. The cablemay contain various equipment, for example, electrical wiring thatconnects signals, power supplies, and grounds between the test head andmainframe cabinet, fiber optic signal connections, and flexible ductingfor air or other gaseous coolants and/or flexible hoses and/or tubingfor liquid coolants for cooling internal components, for example,densely packed very high-speed, precision circuitry.

Cradle 300 holds test head 490 at two points 495 (only one beingvisible), which define an axis that passes approximately through itscenter of gravity. Test head 490 may pivot about this axis. Othercradles and test head holding mechanisms, providing further capabilitiesand more degrees of motion freedom are known in the art and may besubstituted as appropriate for specific applications. Test head 490includes device under test (“dut”) test site 485. Test head 490 is shownin what is known as the “dut up” orientation with the dut test site 485facing up.

As shown in FIGS. 1A and 1B, cradle 300 is held by roll gear box 580,which includes hand wheel 585. Rotating hand wheel 585 drives a wormgear mechanism, which is internal to gear box 580. This worm gearmechanism turns coupling 587 to which cradle 300 is attached. Thus,rotating hand wheel 585 causes rotation of cradle 300 and test head 490about its roll axis. In an exemplary embodiment, roll gear box 580provides plus/minus approximately 95 degrees of roll motion, whichenables test head 490 to be moved to, and placed in, any dut up, dutdown, dut vertical, or intermediate angular position. Roll compliancefor docking may be provided by a number of techniques.

Main arm assembly 500 generally includes main arm plate 510 withpivot-coupling unit 530 attached thereto by means of two horizontallinear rails 515, which are situated in a vertical plane, and bearingsor the like. Roll gear box 580 is pivotally coupled to pivot couplingunit 530 via a pair of journals 512 a, 512 b engaging low frictionbearings 511 a 511 b, or the like, so that roll gear box 580 is free torotate about a vertical axis defined by such pivotal coupling. In anexemplary embodiment, more that 90 degrees of rotation is provided bythe pivotal coupling. Horizontal side-to-side motion is provided bymoving main arm plate 510 along horizontal rails 515 and the associatedbearings.

Roll gear box 580′ of another exemplary embodiment of the presentinvention will be described with reference to FIGS. 3-13. As will bedescribed, roll gear box 580′ includes compliance unit 1600 configuredto facilitate roll compliance. While gear box 580′ will be describedwith reference to pivot coupling unit 530 and cradle 300 of test headmanipulator system 10, it may be utilized with other test headmanipulator systems.

Referring to FIGS. 3-6, roll gear box 580′ includes journal block 1582from which journals 512 a, 512 b extend for pivotal connection withbearings 511 a, 511 b of pivot coupling unit 530. Swing lock mechanism1581 may be provided to lock journal block 1582 relative to pivotcoupling unit 530. Pivot block 1584 is supported by journal block 1582and is configured to support coupling 587′, for example, via a slewingring bearing 591 or the like, for low-friction rotation about a centralaxis thereof. Support coupling 587′ and bearing 591 make up a couplingunit of the present embodiment. As in the previous embodiment, cradle300 is connected to coupling 587′ such that rotation of coupling 587′causes rotation of cradle 300 and test head 490 about its roll axis.

Worm gear unit 1586 is supported by pivot block 1584 and is configuredto provide a controlled rotational output via output shaft 1585. Wormgear shaft 1588 extends across worm gear unit 1586 and includes aninternal worm gear (not shown) that engages and drives output shaft1585. Referring to FIG. 6, end 1589 of worm gear shaft 1588 includes abevel gear 1591 configured to engage output bevel gear 1593 of drivemotor 1590. In the present embodiment, drive motor 1590 is a pneumaticmotor and includes inlets 1592 and 1594 for driving drive motor 1590either in a clockwise or counterclockwise direction. While a pneumaticmotor is illustrated, an electric motor or any other rotational driveunit may be utilized. In the present embodiment, the opposite end 1587of worm gear shaft 1588 is configured to receive a hand wheel or thelike, which may be used in addition to or in place of drive motor 1590,to drive output bevel gear 1593.

The rotational output of output shaft 1585 is transmitted to coupling587′ via roll drive pulley 1606 and drive belt 1608. Roll drive pulley1606 mounts on output shaft 1585 and rotates therewith. Drive belt 1608extends between roll drive pulley 1606 and coupling 587′ and transmitsthe rotational output from roll drive pulley 1606 to coupling 587′. Rolldrive pulley 1606 and coupling 587′ are sized to effect a desired gearratio therebetween. In the present embodiment, the relative sizes ofpulley 1606 and coupling 587′ are selected to give a reasonable rate ofcradle roll rotation in comparison to the speed and torque of drivemotor 1590.

Referring to FIGS. 6 and 7, compliance unit 1600 of the presentembodiment includes a pair of biased idlers 1610A, B. Idlers 1610A, Bare mounted with a spring bias or the like and are free to movehorizontally or, more generally, along a linear axis that isperpendicular to a line through the centers of coupling 587′ and drivepulley 1606. Other ranges of motion may also be utilized. The springmounts urge idlers 1610A, B inwards to provide tension on drive belt1608. With roll drive pulley 1606 in a fixed position, for example withdrive motor 1590 turned off (the back driving forces through thecoupling worm gear may be configured sufficiently high so that drivepulley 1606 is essentially locked), an external rotational force ortorque applied to coupling 587′ will cause coupling 587′ to rotate. Inso doing, one of the idlers 1610A, B will move inwards while the othermoves outwards. For example, with respect to the configurationillustrated in FIG. 7, if coupling 587′ is urged externally to rotateclockwise, right hand idler 1610A moves inwards and left hand idler1610B moves outwards. If coupling 587′ is urged externally to rotatecounterclockwise, left hand idler 1610B moves inwards and right handidler 1610A moves outwards. If the external force or torque is removed,idlers 1610A, 1610B tend to be urged back towards their centralposition, restoring the load to its initial (neutral) position.

While the idlers 1610A, B are illustrated herein with a spring bias,other biasing means may be utilized. For example, the idlers 1610A, Bmay be fluidly biased. Furthermore, such fluid bias may be adjustable.For example, the fluid bias may be adjusted based on an operationcondition of the test head manipulator system, e.g., the fluid bias isincreased when the test head manipulator system is driving the positionof the test head and the fluid bias is lower the when the test head isnot being driven. Other biasing means and configurations may also beutilized.

Having described the general operation of compliance unit 1600, adetailed description of an exemplary configuration of compliance unit1600 will be provided with reference to FIGS. 6-13. Compliance unit 1600includes housing 1602 configured to be mounted to worm gear unit 1586.Housing 1602 includes through bore 1604 configured to receive drivepulley 1606. Cross slot 1605 extends into the top of housing 1602 andintersects with through bore 1604 such that drive belt 1608 passingaround drive pulley 1606 may extend out of housing 1602 and engagecoupling 587′. Cross slot 1605 is also configured to receive idlers1610A, B with such aligned with drive belt 1608 passing through crossslot 1605. In the present embodiment, each idler 1610A, B is supportedon a respective axel 1612A, B. Housing 1602 includes opposed axel slots1613A configured to support ends of axel 1612A for linear motion thereinand opposed axel slots 1613B configured to support ends of axel 1612Bfor linear motion therein. If desired, axel slots 1613A, B may havedifferent configurations than illustrated. A pair of shaft bores 1607extend through housing 1602 parallel to cross slot 1605 with one on eachside of cross slot 1605. Each shaft bore 1607 passes through arespective axel slot 1613A and axel slot 1613B. Cross slot 1605, shaftbores 1607 and axel slots 1613A, B are configured to support idlerassembly 1601 as described hereinafter. An exemplary idler assembly 1601is illustrated in FIGS. 10-13. Idler assembly 1601 includes a pair ofshafts 1620 configured to support axels 1612A, B for linear motiontherealong. Referring to FIG. 11, each shaft 1620 includes travelsurfaces 1622 adjacent each end. Travel surfaces 1622 are configured tosupport axel bushings 1630 for low friction travel therealong. A centralportion of shaft 1620 may be stepped to define travel limit stops 1624at each travel surface 1622. The central portion of shaft 1620 includesgrooves 1625 for receiving retaining clips 1626 that are engaged aftershaft 1620 is positioned in a respective shaft bore 1607 and secureshaft 1620 relative to housing 1602 (see FIG. 9). Each end of shaft 1620includes a threaded bore 1623 configured to receive a respective springscrew 1642, as described hereinafter. Alternatively, each end of shaft1620 may be threaded and configured to receive a nut or the like.

Referring to FIGS. 10 and 12, each idler axel 1612A,B includes centralportion 1614 configured to rotatably support a respective idler 1610A,B. Idler 1610A, B may include bearings or the like (not shown) to reducefriction. Idler grooves 1615 extend about central portion 1614 and areconfigured to receive retaining clips 1619 which axially secure idler1610A, B on axel 1612A, B. In the present embodiment, each end 1616 ofaxel 1612A, B is flattened to define spring contact surfaces 1618,however, contact surfaces 1618 can be configured with any configuration,including a curved configuration. Bushing bore 1617 extends through eachaxel end 1616 and is configured to receive a respective bushing 1630,desirably with an interference fit such that axel 1612A, B moves withbushings 1630 as bushings 1630 slide along the respective shaft travelsurfaces 1622.

Referring to FIGS. 10 and 13, once idler axels 1612A, B and respectivebushings 1630 are positioned on travel surfaces 1622 of shafts 1620, arespective compression spring 1640 is positioned about each travelsurface 1622. A respective spring screw 1642 is extended through eachcompression spring 1640 and engaged in the respective threaded bore 1623at the end of shaft 1620. Washers 1644 may be positioned between springscrews 1642 and compression springs 1640. As spring screw 1642 istightened, compression screw 1640 is compressed against the respectivespring contact surfaces 1618 of axel 1612A, B. In the presentembodiment, compression springs 1640 provide the spring bias describedabove with respect to FIG. 7. Spring screws 1640 may be tightened asdesired to set the tension on drive belt 1608 and establish the initial,neutral position of idlers 1610A, B. Idlers 1610A, B can also beutilized to counteract an out-of-balance torque on coupling 587′ byadjusting the individual spring screws 1640. For example, if the load is600 pounds and the center of gravity is offset ½ inch from the axis ofrotation, there is a torque of 300 in-lbs that will tend to rotate theload in an undesirable way. By adjusting the appropriate spring screws1640, the spring forces acting on idlers 1610A, B may be adjusted tocounteract this out-of-balance torque.

Referring to FIGS. 14A, 14B and 15, compliance unit 1600 is illustratedin use with roll gear boxes 580″, 580′″ having various configurations.Referring specifically to FIGS. 14A and 14B, roll gear box 580″ includesjournal block 1582″ from which journals 512 a, 512 b extend for pivotalconnection with bearings 511 a, 511 b of pivot coupling unit 530. Swinglock mechanism 1581 may be provided to lock journal block 1582″ relativeto pivot coupling unit 530. In the present embodiment, the pivot blockis formed integrally with journal block 1582″. Journal block 1582″ isprovided with a pair of bearings 593 and 595 which are configured tosupport shaft 592 extending from support coupling 587″ for low-frictionrotation about a central axis thereof. Shaft 592 extends through drivemember 596 positioned between support coupling 587″ and journal block1582″. Pins 597 or the like extend between support coupling 587″ anddrive member 592 such that they are rotationally interconnected. A stopbracket 598 may extend from journal block 1582″ adjacent to drive member592. Stops 568 (only one shown) extend radially from each side of drivemember 592 and are configured to contact stop bracket 598 to limit therange of rotation. Cover assembly 599 is provided to protect complianceunit 1600, gear unit 1586, motor 1590, and associated apparatus. Supportcoupling 587″ and drive member 592 make up a coupling unit of thepresent embodiment. As in the previous embodiments, cradle 300 isconnected to coupling 587″ such that rotation of coupling 587″ causesrotation of cradle 300 and test head 490 about its roll axis.

In the present embodiment, compliance unit 1600 is supported by journalblock 1582″. Again, the rotational output of output shaft 1585 of gearunit 1586 is transmitted to coupling 587″ via roll drive pulley 1606 anddrive belt 1608. Roll drive pulley 1606 mounts on output shaft 1585 androtates therewith. In the present embodiment, drive belt 1608 extendsbetween roll drive pulley 1606 and drive member 592. Since drive member592 is rotationally interconnected with coupling 587″, drive belt 1608transmits the rotational output from roll drive pulley 1606 to coupling587″ through drive member 592. Roll drive pulley 1606 and coupling 587″are again sized to effect a desired gear ratio therebetween. In allother aspects, compliance unit 1600 operates in the same manner asdescribed above.

Referring to FIG. 15, roll gear box 580′″ includes journal block 1582′″from which journals 512 a, 512 b extend for pivotal connection withbearings 511 a, 511 b of pivot coupling unit 530. Swing lock mechanism1581 may be provided to lock journal block 1582″ relative to pivotcoupling unit 530. In the present embodiment, journal block 1582′″includes an internal mount 1579 for attachment of stewing ring bearing591. In this embodiment, bearing 591 extends parallel to the body ofjournal block 1582′″. As in the embodiment of FIGS. 3-13, supportcoupling 587′ is connected with bearing 591 for low-friction rotationabout a central axis thereof. Support coupling 587′ and bearing 591 makeup a coupling unit of the present embodiment. As in the previousembodiments, cradle 300 is connected to coupling 587′ such that rotationof coupling 587′ causes rotation of cradle 300 and test head 490 aboutits roll axis.

In the present embodiment (FIG. 15), compliance unit 1600 is supportedby journal block 1582′″ in a different orientation, however, therotational output of output shaft 1585 is still transmitted to coupling587′ via roll drive pulley 1606 and drive belt 1608. Roll drive pulley1606 mounts on output shaft 1585 and rotates therewith. As in theembodiment of FIGS. 3-13, drive belt 1608 extends directly between rolldrive pulley 1606 and coupling 587′, thereby transmitting the rotationaloutput from roll drive pulley 1606 to coupling 587′. Roll drive pulley1606 and coupling 587′ are again sized to effect a desired gear ratiotherebetween. In the present embodiment, the gears 1591′″ and 1593′″ ofthe worm gear unit 1586 and the motor 1590 have a straight connectionrather than a beveled connection. In all other aspects, compliance unit1600 operates in the same manner as described above.

Whereas the rotational axis defined by the axis of rotation of couplingunit 587′ of the embodiments described in FIGS. 3-6 and FIGS. 14A and14B essentially intersects the orthogonal axis defined by journals 512 aand 512 b, the rotational axis defined by coupling unit 587′ of theembodiment of FIG. 15 is located to one side of the orthogonal axisdefined by pivot journals 512 a and 512 b as might be required incertain applications. In all embodiments it is desirable that the loadbe balanced with respect to the axis of rotation. This may be achievedby attaching the load so that the axis of rotation passes substantiallythrough the center of gravity of the load. If it is desired that theaxis is to be located away from the load's center of gravity. Then loadbalancing apparatus such as is disclosed in U.S. Pat. No. 7,084,358 tothe same assignee may be incorporated.

Referring again to FIGS. 1A-2C, column unit 100 includes two linearrails 115 which extend vertically from approximately the bottom to thetop thereof. Main arm plate 510 is coupled to rails 115 with appropriatelinear bearings or the like. Main fluid-operated actuator 150 (see FIG.37A) within column 100 is associated with main arm plate 510, enablingmain arm plate 510 and its attached load (comprising main arm assembly500, roll gear box 580, cradle 300, test head 490 and cable) to be movedup and down in the vertical direction along rails 115. Such a fluidactuated manipulator 10 is configured to be of the fluid-balanced typedescribed by Smith, first at U.S. Pat. No. 4,589,815 (See, e.g., FIGS.38 through 12), and subsequently at U.S. Pat. Nos. 4,705,447 and5,149,029. These three patents are herein incorporated by reference intheir entirety. As described in these patents, a substantiallyweightless condition (thus compliant motion) is provided in the verticalor Y-axis. As will be disclosed in more detail, the mechanism internalto column 100 enables the test head to be moved an enhanced verticaldistance, for example, twice the distance moved by the piston within thepneumatic cylinder.

Base unit 600 includes horizontally oriented base plate 605 which isgenerally stationary when system 10 is in operation. Linear rails 630are provided on base plate 605. Linear bearings or the like couplehorizontal carriage 650 to linear rails 630 such that horizontalcarriage 650 is readily linearly moveable in a plane parallel to thefloor. This linear motion defines the in-out axis. Column unit 100 issecurely attached to horizontal carriage 650 and is thereby providedwith in-out linear motion relative to base unit 600. As will bedescribed, a pneumatic cylinder may be included in base unit 600 toprovide powered in-out motion.

FIG. 1A shows a Cartesian coordinate system which is used herein. TheX-axis 1002 is oriented in a horizontal plane which is parallel with thefloor, base plate 605 and horizontal linear rails 515 such thathorizontal side-to-side motion is parallel with X-axis 1002. Z-axis 1004is also in a horizontal plane, which is parallel with the floor and baseplate 605, and also parallel with linear rails 630 located on horizontalcarriage 650 such that in-out motion is parallel with Z-axis 1004.Y-axis 1006 is vertical and parallel with linear rails 115 such thatup-down motion is parallel with Y-axis 1006. X-axis 1002, Y-axis 1006and Z-axis 1004 are all mutually orthogonal.

An exemplary control unit 700 will be described in greater detailhereinafter. Control unit 700 generally includes push buttons, switchesor the like to enable an operator to affect control over the up-down andin-out motions.

Referring to FIGS. 1A and 2A-2C, various positions of manipulator system10 are shown, illustrating an exemplary range of motion of manipulatorsystem 10. In FIG. 1A, the vertical position of test head 490 ispart-way up vertical column 100 at a location known as the “serviceposition.” Also in FIG. 1A, test head 490 is swung 45 degrees right fromZ-axis 1040, and the horizontal position is full right. In FIG. 2A, testhead 490 is at its lowest point, at a swing angle of zero degrees, andfully to the left. In FIG. 2B, test head 490 is at its highest position,at a swing angle of 90 degrees, and fully to the right. In FIG. 2C, testhead 490 is at its highest position, at a swing angle of zero degrees,and fully to the left.

Referring to FIGS. 16A and 16B, base unit 600 will be described in moredetail. Base unit 600 supports and provides in-out motion for column 100and thereby test head 490. Column 100 (not shown in FIGS. 16A and 16B)is mounted on carriage 650. Carriage 650 attaches with linear bearings635 a,b,c,d to linear rails 630 a,b, which are mounted parallel to oneanother on bottom plate 605. Thus, carriage 650 may move horizontallyalong an axis defined by linear rails 630 a and 630 b. In the presentembodiment, dual-action pneumatic cylinder 620 is provided as a motionactuator to affect horizontal in-out motion of carriage 650, column 100,and, consequently test head 490. Motion-limiting stop blocks 628 f,rfixed to bottom plate 605 in cooperation with stop unit 640 attached tothe underside of carriage 650 are provided to stop and constrain forwardand rearward motion respectively of carriage 650 as described in moredetail below.

Bottom plate 605 is preferably manufactured from steel for strength andminimal flexing as the load is moved from one position to another. Othermaterials, including metallic and non-metallic materials, may also beutilized. In the present embodiment, parallel linear rails 630 a,b andsolid side rails 606 a,b are attached to base 605 with socket-head capscrews. Other attachment means may alternatively be utilized. Solid siderails 606 a,b preferably provide additional resistance to flexing. Fourcaster brackets 602 are attached to base plate 605; one in proximity toeach of its corners. A different number and arrangement of casterbrackets 602 may alternatively be utilized. Attached to each bracket 602is a caster wheel 601. Caster wheels 601 may be of the fixed orswiveling type according to application requirements. Other types ofwheels may also be utilized. Also attached to base plate 605 are anumber of extension legs to provide stability as the test head is movedthroughout its motion envelope. The illustrated extension legs includefront corner extension legs 613 and side extension legs 607. Rear cornerextension leg 610 may be extended under the mainframe cabinet of an ATEsystem to provide further stability.

Base unit 600 desirably includes leveling supports 603 coupled to baseplate 605, leveling supports 614 coupled to extension legs 613, andleveling supports 608 coupled to extension legs 607. These are of theconventional type, having a round flat surface, which faces downwards,and a threaded portion, which extends upwards and engages anappropriately threaded hole in the member to which it is attached. Rearcorner extension leg 610 includes leveling support 611 that is mountedin an upside-down orientation. Support 611 is used to engage rear cornerextension leg 610 with the ATE mainframe cabinet (not shown).

Prior to use of manipulator system 10, leveling supports 603, 608, and614 are desirably rotated so that their flat surfaces are in contactwith the floor and caster wheels 601 are positioned slightly above thefloor. Supports 603, 608, and 614 may be adjusted in order to level base600 and to place column 100 in a desirably vertical position. Alsosupport 611 is rotated so that it is in engagement with the ATE cabinet(not shown). Manipulator system 10 may be moved from one location toanother across a reasonably level floor by screwing all levelingsupports inwards so that leveling supports 603, 608, and 614 are clearof the floor and support 611 is disengaged from the cabinet. Withcoaster wheels 601 in contact with the floor, manipulator system 10 maybe readily rolled to a new location.

Horizontal carriage 650 is provided to support column 10 and to providein-out (forward-reverse) motion for test head 490. Like base plate 605,rectangular carriage 650 is preferably made of steel for strength andresistance to flexing. A linear bearing 635 is attached at each cornerof carriage 650 with six socket head cap screws. Linear bearings 635 aredesirably attached so as to be in precise engagement with linear rails630 a,b such that carriage 650 may be readily moved along a linearin-out axis with very low friction. A lock mechanism may also beprovided to hold carriage 650 in a desired position within its range ofmotion. In the present embodiment, the lock mechanism includes shoe 692,located on the underside of carriage 650, and toggle control 690,located on the upper, operator-accessible side of carriage 650. Asshown, shoe 692 is aligned with rail 630 b. With toggle control in afirst, unlocked position, shoe 692 is located slightly above or in loosecontact with rail 630 b, and the carriage may be readily moved alongrails 630 a,b. When the carriage has been placed in its desiredposition, toggle 690 may be moved to a second, locked position. Whentoggle 690 is in the locked position, shoe 692 bears strongly againstrail 630 b, inhibiting further motion of carriage 650 along rails 630a,b.

Stop blocks 628 f and 628 r are secured to base plate 605 withappropriate screws or the like. Stop blocks 628 f and 628 r arepreferably centered on a line which is parallel to rails 630 a,b. Stopblock 628 f is located towards the front of base plate 605 and stopblock 628 r is located towards the rear. Both stop blocks 628 f,r areoriented so that each has a planar face directed towards the center ofbase plate 605 and which is perpendicular to rails 630 a,b. Carriagestop unit 640 is attached to the underside of horizontal carriage 650using appropriate screws or the like. Stop unit 640 includes stop cones642 f and 642 r, which are preferably made of hard rubber or othersuitable material. Carriage stop unit 640 is located on carriage 650such that, when carriage 650 is coupled to rails 630 a,b by means oflinear bearings 635, it is positioned both: (1) between stop blocks 628f and 628 r and (2) with the axes of stop cones 642 f,r aligned with aline extending between the centers of stop blocks 628 f and 628 r.Horizontal carriage 650 may be moved towards the front until stop cone642 f engages stop block 628 f, and it may be moved rearwards until stopcone 642 r engages stop block 628 r. The net horizontal linear motion islimited to a distance being the distance between the inwards facingfaces of stop blocks 628 f and 628 r minus the distance between the tipsof stop cones 642 f and 642 r.

Due to the low friction couplings between rails 630 a,b and linearbearings 635, the horizontal motion for relatively small manipulatorsand test heads may be provided manually. However, for larger systems,many users prefer to have powered motion in this axis. In such anarrangement, a compliant mode, where the load may be readily moved by arelatively small external force (including manual) for docking of thetest head with a peripheral or possibly other reasons, is preferablyprovided. In the present embodiment, dual-action pneumatic cylinder 620is configured to provide such compliant mode. Dual action pneumaticcylinder 620 and the associated piston rod 622 are attached withappropriate fastening means to base plate 605. Pneumatic cylinder 620and piston rod 622 are preferably located so that the common axis ofcylinder 620 and piston rod 622 is parallel to linear rails 630 a,b. Inthe present embodiment, distal end 623 of piston rod 622 is threaded.Distal end 623 passes through a circular hole in bracket 625 which ismounted near the edge of carriage 650. A nut (not shown) is threadedonto distal end 623 of rod 622 such that piston rod 622 is attached tocarriage 650. Other attachment arrangements may also be utilized.

Cylinder 620 is equipped with two ports, one on either side of theinternal piston (not shown). Fluid is injected under pressure into oneof the ports to urge the piston and piston rod 622 in a first directionand into the other port to urge the piston and piston rod 622 in theopposite direction. Motion in one direction or the other may be enhancedif the port that is not receiving fluid injection is left open so as toallow fluid retained from a previous motion to be vented. Thus, bycontrolling the flow of pressurized fluid into and out of the two ports,as described hereinafter, motion of the horizontal carriage 650 may becontrolled. Preferably, stop blocks 628 f and 628 r are arranged withrespect to carriage stop unit 640 so that the range of motion ofcarriage 650 is less than the total available stroke of the pistonwithin cylinder 620 and so that the carriage is forced to stop beforethe piston reaches the end of its stroke (that is, before bottoming out)in either direction. This insures that there is always a sufficientvolume within the cylinder to initiate motion away from a stop. With theuse of pneumatics, the locking mechanism including shoe 692 may utilizea pneumatic toggle 690′ in place of the toggle 690 described above.Pneumatic toggle 690′ includes fluid actuator 691 (see FIG. 57) whichhas a default unlocked retracted position such that shoe 692 is spacedfrom rail 630 b, similar to the unlocked condition as described above.To lock the in/out motion via shoe 692, control valve 693 is actuated,for example, via a toggle switch, whereby fluid actuator 691 extendsshoe 692, thereby locking the system against in or out movement.

In the present embodiment, the working fluid is air, which iscompressible. Thus, if the carriage is in a stationary situation inwhich air is not being added or released at either port, the carriagemay be moved by applying an external force. Accordingly, compliance isprovided. Alternatively, as illustrated in the current embodiment, iffluid pressure is released and the ports opened to the atmosphere, thecarriage and its supported load may be moved manually through the rangefrom one stop to the other. As will be described hereinafter, control ofthe horizontal motion via cylinder 620 is preferably provided incombination with the control of other manipulator axes by means ofcontrol unit 700.

Referring to FIGS. 17-32, an alternative exemplary base unit 600′ willbe described in more detail. Base unit 600′ supports and provides in-outmotion for column 100 and thereby test head 490. Column 100 (not shownin FIGS. 17-20) is mounted on carriage 650′. Carriage 650′ attaches withlinear bearings 635 a,b,c,d to linear rails 630 a,b, which are mountedparallel to one another on bottom plate 605′. Thus, carriage 650′ maymove horizontally along an axis defined by linear rails 630 a and 630 b.As described in more detail hereinafter, linear actuator assembly 50 isprovided as a motion actuator to affect horizontal in-out motion ofcarriage 650′, column 100, and, consequently test head 490.Motion-limiting stop blocks 628 f,r fixed to bottom plate 605′ incooperation with stop unit 640 attached to the underside of carriage650′ are provided to stop and constrain forward and rearward motionrespectively of carriage 650′ as described in more detail below.

Bottom plate 605′ is preferably manufactured from steel for strength andminimal flexing as the load is moved from one position to another. Othermaterials, including metallic and non-metallic materials, may also beutilized. In the present embodiment, parallel linear rails 630 a,b andsolid side rails 606 a,b are attached to base 605′ with socket-head capscrews. Other attachment means may alternatively be utilized. Solid siderails 606 a,b preferably provide additional resistance to flexing. Fourcaster brackets 602 are attached to base plate 605′; one in proximity toeach of its corners. A different number and arrangement of casterbrackets 602 may alternatively be utilized. Attached to each bracket 602is a caster wheel 601. Caster wheels 601 may be of the fixed orswiveling type according to application requirements. Other types ofwheels may also be utilized. Also attached to base plate 605′ are anumber of extension legs to provide stability as the test head is movedthrough out its motion envelope. The illustrated extension legs includefront corner extension legs 613 and side extension legs 607. Rear cornerextension leg 610 may be extended under the mainframe cabinet of an ATEsystem to provide further stability.

Base unit 600′ desirably includes leveling supports 603 coupled to baseplate 605′, leveling supports 614 coupled to extension legs 613, andleveling supports 608 coupled to extension legs 607. These are of theconventional type, having a round flat surface, which faces downwards,and a threaded portion, which extends upwards and engages anappropriately threaded hole in the member to which it is attached. Rearcorner extension leg 610 includes leveling support 611 that is mountedin an upside-down orientation. Support 611 is used to engage rear cornerextension leg 610 with the ATE mainframe cabinet (not shown).

Prior to use of manipulator system 10, leveling supports 603, 608, and614 are desirably rotated so that their flat surfaces are in contactwith the floor and caster wheels 601 are positioned slightly above thefloor. Supports 603, 608, and 614 may be adjusted in order to level base600′ and to place column 100 in a desirably vertical position. Alsosupport 611 is rotated so that it is in engagement with the ATE cabinet(not shown). Manipulator system 10 may be moved from one location toanother across a reasonably level floor by screwing all levelingsupports inwards so that leveling supports 603, 608, and 614 are clearof the floor and support 611 is disengaged from the cabinet. With casterwheels 601 in contact with the floor, manipulator system 10 may bereadily rolled to a new location.

Horizontal carriage 650′ is provided to support column 10 and to providein-out (forward-reverse) motion for test head 490. Like base plate 605′,rectangular carriage 650′ is preferably made of steel for strength andresistance to flexing. A linear bearing 635 is attached at each cornerof carriage 650′ with six socket head cap screws. Linear bearings 635are desirably attached so as to be in precise engagement with linearrails 630 a,b such that carriage 650′ may be readily moved along alinear in-out axis with very low friction.

Stop blocks 628 f and 628 r are secured to base plate 605′ withappropriate screws or the like. Stop blocks 628 f and 628 r arepreferably centered on a is line which is parallel to rails 630 a,b.Stop block 628 f is located towards the front of base plate 605′ andstop block 628 r is located towards the rear. Both stop blocks 628 f,rare oriented so that each has a planar face directed towards the centerof base plate 605′ and which is perpendicular to rails 630 a,b. Carriagestop unit 640 is attached to the underside of horizontal carriage 650′using appropriate screws or the like. Stop unit 640 includes stop cones642 f and 642 r, which are preferably made of hard rubber or othersuitable material. Carriage stop unit 640 is located on carriage 650′such that, when carriage 650′ is coupled to rails 630 a,b by means oflinear bearings 635, it is positioned both: (1) between stop blocks 628f and 628 r and (2) with the axes of stop cones 642 f,r aligned with aline extending between the centers of stop blocks 628 f and 628 r.Horizontal carriage 650′ may be moved towards the front until stop cone642 f engages stop block 628 f, and it may be moved rearwards until stopcone 642 r engages stop block 628 r. The net horizontal linear motion islimited to a distance being the distance between the inwards facingfaces of stop blocks 628 f and 628 r minus the distance between the tipsof stop cones 642 f and 642 r.

Referring to FIG. 20, the actuator 50 generally comprises a carriageplate 1, a pair of ramp blocks 2, a brake shoe 3, a flange 4, a bearingblock 5, a fluid actuated cylinder 6, a pair of bearings 7, a pair ofrails 8, a pair of non-return valves 9, self sticking foam pads 10,magnets 11, anti-slide rubber pads 12, a pair of sleeve bearings 13,dowel pins 14, cylinder head bolts 15, a plurality of countersunk socketscrews 16, 17, a plurality of cylinder head bolts 18, 19, and a hex nut20. Referring to FIG. 19, the cylinder 6 is pivotally attached to thecarriage 605′ at one end via the flange 4 and bearing block 5. At theopposite end, piston rod 26 is connected to brake shoe 3. Brake shoe 3includes a pair of opposed dowel pins 14. Each dowel pin 14 extends intoa ramped slot 22 in a respective ramp block 2. Ramp blocks 2 are eachconnected to carriage plate 1, which is attached via bearings 7 to rails8 to provide linear motion therealong. As explained in greater detailhereinafter, movement of piston rod 26 causes movement of the pins 14along the ramped slots 22 and thereby controls application of the brakeshoe 3.

The present embodiment provides a compliant mode, where the load may bereadily moved by a relatively small external force (including manual)for docking of the test head with a peripheral or possibly otherreasons. In the present embodiment, actuator 50 is configured to providesuch compliant mode. Cylinder 6 is equipped with two ports 9, one oneither side of the internal piston (not shown). In the presentembodiment, to achieve compliance, either fluid pressure is released andthe ports 9 opened to the atmosphere or fluid is supplied to the retractport 9 such that the brake shoe 3 is not applied, as describedhereinafter. With the brake shoe 3 in a non-applied position, thecarriage 650′ and its supported load may be moved manually through therange from one stop to the other.

Automatic movement of carriage 650′ in a first, docking direction isalso provided in the present embodiment. The system may also beconfigured to provide automated movement in both directions. Fluid isinjected under pressure into one of the ports 9 to urge the piston andpiston rod 26 in an opposite direction, thereby applying the brake shoe3 and moving the carriage 650′ in the first, docking direction. Fluid isinjected into the other port to urge the piston and piston rod 26 in theopposite direction to release the brake shoe 3, wherein the carriage650′ may be moved manually. Alternatively, a separate bias member, forexample, a spring, may be provided such that the piston is automaticallyretracted when fluid pressure is released. Thus, by controlling the flowof pressurized fluid into and out of the two ports 9, motion of thehorizontal carriage 650′ may be controlled.

As indicated above, extension and retraction of piston rod 26 alsocontrols application of brake shoe 3, as will be described withreference to FIGS. 21-32. Referring to FIGS. 21-23, this is an initialposition and the piston 26 is retracted in its cylinder 6. Thus, thedowel pins 14 are at the upper ends of their ramps 22 (see FIG. 22A),and the brake shoe 3 is raised so that it is not touching the base plate605′ (see FIG. 23A) or the “traction screw heads” extending uptherefrom. The piston 26 may be held in this position by applying fluidpressure to the retract port 9. Alternatively, a spring or otherstructure may be used to hold the piston 26. In this condition, thecarriage 650′ and the load sitting on it may be freely moved along therails 630 a,b with bearings 635.

Referring to FIGS. 24-26, the fluid control has been switched to the“Drive” or “Extend” position. Fluid pressure is released from the port 9which was holding the piston 26 in its retracted position (i.e., theretract port). Fluid pressure is applied to the port 9 which causes thecylinder 6 to extend, i.e., the extend port. The cylinder 6 has extendeda small distance moving dowel pins 14 along in their ramps 22 as is moreclearly seen in FIG. 25A. The brake shoe 3 is now closer to the baseplate 605′, but is still not touching the base plate 605′ or the“traction screw heads” extending up therefrom, as shown in FIG. 26A. Thecarriage 650′ has not moved yet.

Referring now to FIGS. 27-29, fluid pressure has continued to be appliedto the extend port 9 by holding the switch in the drive or extendposition. Consequently, the cylinder 6 is now fully extended, and thedowel pins 14 have moved downwards along their ramps 22, as shown inFIG. 28A. As is seen more clearly in FIG. 29A, the brake shoe 3 hascontacted the base plate 605′ and the tops of the “traction screwheads”. As such, the shoe 3 is “pushing” against the base plate 605′,and, as the cylinder 6 has extended, this has caused the carriage 650′to move to the right. Notice that the dowel pins 14 are not all the wayat the lowest ends of their ramps 22. This has been designed in thismanner to allow and compensate for wear of the brake shoe 3 and brakepads 12. As these items wear, the dowel pins 14 will travel further downthe ramps 22.

Referring to FIGS. 30-32, the control has now been switched to the“retract” position. Fluid pressure has been removed from the extend port9, which is allowed to vent. Fluid pressure has been applied to theretract port 9, and the piston 26 has retracted. The system 50 is nowready for another motion cycle. That is, if the control is switchedagain to the extend position, pressure will again be applied to theextend port 9 while the retract port 9 is vented. This will cause thecylinder 6 to extend once more, causing the carriage 650′ to be pushedfurther to the right. To return the carriage 650′ to its startingposition (to the left), we leave the switch in the retract position, andthis allows the carriage 650′ to be manually pushed along its motionrails.

Column unit 100 will be described in more detail with reference to FIGS.33A-42C. In these figures, column unit 100 is generally illustrated withmain arm assembly 500, but, for simplicity, roll gear box 580, cradle300, test head 490, base unit 600, and control unit 700 are omittedtherefrom.

Referring to FIGS. 34A-34C, column unit 100 includes column body 110,which provides a vertical support structure as well as an enclosure unitand mounting structure for various apparatus. In the present embodiment,column body 110 is U-shaped in cross section and fabricated of asuitable material, such as steel, in appropriate dimensions to supportthe desired load. The U-shaped cross section provides a structure withthree contiguous closed sides (right side 101, left side 102 and rearside 103) and an open (front) side 115. Attached to the bottom of columnbody 110 is footplate 111, which includes footplate opening 111 a.Footplate 111 is used to secure column assembly 100 to base plate 605 ofbase unit 600. Because footplate 111 transfers the load from column unit100 to base unit 600, footplate 111 it is preferably welded to columnbody 110.

Top piece 112 is fitted to the top of column body 110 and attachedthereto with screws or other means. Attached to left side 101 of columnbody 110 is bolt lock assembly 116, which includes slidable bolt 116 aand bolt operating handle 116 b. Inside column body 110 are structuralmembers 117. Additional structural members 118 are secured across frontopening 115 and located at the approximate center of opening 115.

Vertically oriented rail-mounting surface 119 is provided on the left ofopen side 115. Two vertically oriented rail-mounting surfaces 121 and122 are provided on the right of open side 115. Preferably, mountingsurfaces 119, 121, and 122 include appropriately located threaded holes123 for receiving screws or the like, which attach rails to therespective surfaces. Other mounting arrangements may also be utilized.

Returning to FIGS. 33A and 33B, linear guide rails 120 a and 120 b arefastened to rail-mounting surfaces 119 and 121 respectively, and toothedbrake-rail 124 is attached to rail-mounting surface 122. Main arm plate510 of main arm unit 500 includes linear bearings 505 a,b,c and d(linear bearings 505 c and d are not visible in FIGS. 33A and 33B.)Linear bearings 505 b and d are arranged so as to engage linear rail 120a, and linear bearings 505 a and c are arranged so as to engage linearrail 120 b such that main arm unit 500 may translate vertically withvery little friction along a vertical axis defined by linear rails 120 aand b. Lift arm 128 includes linear bearings 125 a and b, which arearranged to engage linear rails 120 a and b respectively such that liftarm 128 may also translate vertically with low friction along the samevertical axis. In the present embodiment, the vertical motion of liftarm 128 is constrained to be between a location approximately just abovethe upper of structural members 118 to approximately just below toppiece 112. Fan folded shields 126 a and 126 b or the like are providedto close opening 115 between lift arm 128 and structural members 118 andbetween lift arm 128 and top piece 112 respectively. Solid shield 127(see FIG. 35B) fills opening 115 below structural members 118.

Main arm unit 500 includes pneumatic lock module 575. Lock module 575includes a pinion gear (not shown) that engages toothed brake rail 124.When air pressure is applied to lock module 575, the pinion gear is freeto rotate; when air pressure is removed, the pinion gear is locked inplace and cannot rotate. Thus, in the absence of air pressure, lockmodule 575 prevents vertical motion of main arm unit 500.

An alternative main arm unit 500′ with a lower profile lock module 575′is illustrated in FIGS. 33C-33E. The lock module 575′ includes shaft 574extending through main arm plate 510 with pinion gear 576 extendingtherefrom (see FIG. 33E). Pinion gear 576 is configured to engagetoothed brake rail 124. As in the previous embodiment, lock module 575′is configured such that when air pressure is applied to lock module575′, pinion gear 576 is free to rotate, and when air pressure isremoved, pinion gear 576 is locked in place and cannot rotate. Thus, inthe absence of air pressure, lock module 575′ prevents vertical motionof main arm unit 500.

Lock module 575′ also includes a rotary damper 578 which engages a rearend of shaft 574. Damper 578 includes a sealed chamber with one or morevanes (not shown) positioned therein and configured to rotate with shaft574. The vanes move within fluid filled pressure chambers and provide adampening effect which may be beneficial if there is “sticking” or thelike during actuation of the system. Damper 574 resists changes inmomentum. Thus, while arm plate 510 is in motion, pinion gear 576rotates due to its interaction with toothed rail 124. This causes shaft574 to rotate causing the vanes within damper 578 to rotate. Any effect,such as overcoming breakaway stiction, that would cause the speed ofplate 510 to change abruptly is resisted and dampened by the viscousresistance of the vanes interacting with the fluid. An exemplary damper578 is the FDT series available from ACE Controls Inc. located inFarmington Hills, Mich. The rotary damper 578 may be utilized with anyof the embodiments described herein.

Main arm unit 500 also includes bolt receiver 123 which includes boltreceiving hole 123 a (see FIG. 37A). Main arm unit 500 may be verticallypositioned so that receiving hole 123 a is aligned with bolt 116 a ofbolt lock assembly 116. Bolt operating handle 116 b may then be operatedto slide bolt 116 a into receiving hole 123 a, thus locking main armunit 500 securely in position. This position is referred to as the“service position.” When in the service position, the system may besafely disassembled/assembled or otherwise worked upon. In particular,support straps 130 a and 130 b, described below, may be safely removed,installed, or replaced.

FIGS. 35A and 35B illustrate main arm unit 500 and lift arm 128 in theirlowest and uppermost positions respectively. As will be explained inmore detail hereinafter, it is observable that main arm unit 500 moves adistance 106 that is greater than, preferably at least twice as great,the distance 107 that lift arm 128 moves.

Referring to FIGS. 36A-36C and 37A-37C, main arm unit 500 is supportedby two straps 130 a and 130 b which are secured to the back of main armplate 510 and which are routed behind lift arm 128 and back into theinterior of column body 110 where they interact with acounterbalance/actuation mechanism as described below. In FIG. 37C theattachment of load carrying straps 130 a,b to the rear of main arm plate510 is visible. In particular the ends of load carrying straps 130 a,bterminate in metallic attachment blocks 131 a,b respectively, which arein turn secured to the rear of is main arm plate 510 with appropriatefasteners or the like, such as machine screws. Further, as best seen inFIG. 36B, the opposite ends of load carrying straps 130 a,b alsoterminate in metallic attachment blocks 131 c,d, which are in turnsecured to the inside rear portion of column body 110.

Thus, the weight of main arm unit 500 and the load that it carries(hereinafter the “total load”) is transferred via load-carrying straps130 a,b to column body 110. Those having a reasonable familiarity withthe art will recognize that one load-carrying strap could be used inplace of two. However, using two load-carrying straps providesredundancy and safety in the event of the failure of one strap. Ofcourse it may be feasible to use more than two load-carrying straps.Also, it will be recognized that wire cables, wire ropes, bicycle-stylechain, and the like may be substituted for the straps.

In the assembled condition, load carrying straps 130 a,b extend upwardsfrom main arm unit 500, about pulley lift carriage 140 and finallydownwards to the attachment blocks 131 c, d. An exemplary pulley liftcarriage 140 is shown in FIG. 39. Pulley lift carriage 140 includes sidebars 141 a and 141 b. Spacer bars 144 are fitted and secured withappropriate fasteners between sidebars 141 a and 141 b to space themapart and parallel with one another. Axels 143 a and 143 b extend fromside bar 141 a to side bar 141 b. Pulleys 142 a,c are mounted,side-by-side, on axel 143 a with suitable bearings. Similarly pulleys142 b,d are mounted, side-by-side, on axel 143 d with suitable bearings.Pulleys 142 a,b,c,d are located between side bars 141 a,b such that theyrotate about axes which are perpendicular to side bars 141 a,b andparallel to spacer bars 144. Load carrying straps 130 a,b extend upwardsfrom main arm unit 500, through the space between lift arm 128 andpulleys 142 a and 142 c, respectively, horizontally across pulleys 142a,b and 142 c,d, respectively, and downwards to the attachment blocks131 c, d.

Lift arm 128 is attached to a forward-facing end of sidebars 141 a and141 b with appropriate screws. Lift arm 128 includes recesses 129 a,b,which receive linear bearings 125 a,b (see FIG. 36A) such that liftcarriage 140 may translate vertically, guided by the interaction oflinear rails 120 a,b with linear bearings 125 a,b.

To facilitate up and down movement of main arm unit 500, pulley liftunit 140 is attached to main fluid-operated actuator 150. Referring toFIG. 38, main fluid-operated actuator 150 includes cylinder block 151which has a cylindrical internal bore and a cylindrical piston whichtravels along the bore in response to a difference in the forces appliedto the two surfaces of the piston which are orthogonal to the axis ofthe cylinder. In this exemplary embodiment, the working fluid is a gas,in particular air. Piston rod 152 extends from one end of cylinder block151. Piston rod 152 is connected to the aforementioned piston, which isinternal to block 151. A compensation coupling 155 (e.g. an“ausgleichskupplung” from Konstandin GmbH, Industriestrasse 13-15,D-76307 Karlsbad, Germany), which provides several degrees of motionfreedom, may be used to couple piston rod 152 to load attachment bracket158. The motion freedom provided by compensation coupling 155compensates for any misalignment between attachment bracket 158 andpiston rod 152, thus reducing any misalignment-induced side loading thatcould impede smooth motion. A first end of coupling member 155 iscoupled to piston rod 152 by means of first joint 154 and to loadattachment bracket 158 with second joint 156. Load attachment bracket158 is attached to spacer bars 141 of pulley lift carriage 140. Pulleylift carriage 140 is thereby coupled to the piston of mainfluid-operated actuator 150 through two flexible joints 154 and 156 andcoupling member 155, the combination of which provides a universaljoint. As such, a load transferred to load attachment unit 158 will betransferred to piston rod 152 in a location and direction that iscoaxial with the axis of piston rod 152 and the cylinder within cylinderblock 151.

Referring to FIG. 40, the tension combined in load-carrying straps 130a,b supports the “total load.” Pulley lift carriage 140 includes twopulleys 142, representing actual lift carriage 140 and pulleys 142a,b,c,d. Strap 130 represents the combination of load carrying straps130 a,b. The tension in strap 130 is shown as W acting downwards andtangentially at each pulley 142. (The force W representing the weight ofthe total load.) Thus, the total force acting downwards on pulley liftcarriage 140 is 2 W. Pulley lift carriage 140 is supported by piston rod152, which is in turn supported by piston 130 within cylinder block 151.To hold lift carriage in static equilibrium or to allow it to be movedat a constant speed, piston rod 152 and piston 153 exert an opposingforce of 2 W in the upwards direction onto lift carriage 140. Thus, theworking fluid applied to cylinder block 151 must provide a pressuresufficient to generate a net upwards force on piston 152 ofapproximately 2 W.

Thus, in exemplary manipulator system 10, fluid-operated actuator 150must support and provide motion to a load that is approximately twicethe weight of main arm unit 500 and its attached load. Both static anddynamic friction also will come into play in any practical embodiment.Static friction acts to help to a small degree to support the load whenit is stationary. Dynamic friction may act in a direction to opposemotion when the load is moving.

With reference to FIG. 65, when the system is properly leveled andsupported and when the load of main arm assembly 500 properly tensionsstraps 130 a and 130 b, the loading on fluid-operated actuator 150 bystraps 130 a and 130 b is such that it tends to keep fluid-operatedactuator 150 in a vertical orientation. FIG. 65 includes free bodydiagrams of pulleys 142 and illustrates the forces acting on each pulley142. In each case, the tension in carrying strap 130 is equal to W andacts in the directions shown. As such, each pulley's axel 143 exerts aforce of square root of two multiplied by the supported weight W in adirection that is 45 degrees from the horizontal and directed outwardsfrom lift carriage 140. Thus, the forces or loading imposed upon liftcarriage 140 by the carrying straps 130 are of the same magnitude, butin opposing directions; that is acting downwards and towards the centerof lift carriage 140. It is seen that these forces will tend to keepfluid-actuated cylinder in a vertical orientation. However, if thetension in straps 130 is removed for any reason, these stabilizingforces would vanish. While opening 111 a closely surrounds the bottom159 of fluid-operated actuator 150 and thereby constrains such fromsignificant movements in the horizontal plane, when the stabilizingforces are removed, for example, during assembly, shipment, setup, ormaintenance, a tipping force may result on the fluid-operated actuator150. In the present embodiment, such tipping is counteracted by means ofthe connection of lift carriage 140 to rails 120 a and 120 b via liftarm 128 and linear bearings 125 a and 125 b.

Again referring to explanatory FIG. 40, the piston may be caused to moveby controlling the working fluid. For example, if air is vented fromcylinder block 151 below piston 152, the pressure in the cylinder andthe upwards force on piston 152 will both begin to decrease, causingpiston 152 to move downwards. Conversely, if fluid is added to cylinderblock 151 below piston 152, the pressure in the cylinder and the upwardsforce acting on piston 152 will begin to increase, causing piston 152 tomove upwards. By regulating the fluid pressure, for example, via thecontrol unit 700 described herein, piston 152 and the load coupled tomay be moved upwards or downwards at a near constant rate necessary tomaintain equilibrium.

FIGS. 41A and 41B are illustrative schematic diagrams which illustratethe vertical motion provided by the column assembly of the presentinvention. As illustrated, one end of strap 130 is shown coupled to afixed location 1205 on reference line 1206 and a load 1210 attached tothe second end. In comparison to the exemplary embodiment manipulatorsystem 10, this corresponds to the attachments of load carrying straps130 a,b to the interior of column body rear 103 and to main arm unit500, respectively. Load 1210 is used in place of main arm assembly 500.In FIG. 41A, pulley lift carriage 140 is positioned so that the centersof pulleys 142 are positioned a distance (1214) 2½ units above referenceline 1206, and the over all length of load carrying strap 130 is suchthat load 1210 is a distance (1213) 1 unit below the centers of pulleys142. Thus, load 1210 is located 2½−1=1½ units above reference line 1206.Suppose that piston 153, piston rod 152, and load carrying carriage 140are all raised a distance (1211) of ½ units. Such raised position isillustrated in FIG. 41B. Distance 1214 between the centers of pulleys142 and reference line 1206 accordingly has increased by ½ unit to 3units. Because the overall length of carrying strap 130 cannot change,distance 1213 from the center of pulleys 142 to load 1210 must bereduced by ½ a unit, i.e. from 1 unit to ½ a unit. Load 1210 is now3−½=2½ units above reference line 1206. Thus, load 1210 has moved atotal distance 1212 of 2½−1½=1 units; whereas, piston 153, piston rod152, and pulley lift carriage 140 have moved only ½ a unit. Accordingly,in this embodiment, the load 1210 moves twice the distance that piston152 moves.

Thus, the arrangement illustrated schematically by FIGS. 40, 41A, and41B enables a load to be moved a distance corresponding to twice thestroke of an actuator; that is to say, the actuator's stroke is doubled.However, the actuator must be capable of supporting twice the weight ofthe load. In the case of a fluid-operated actuator, the applied force isproportional to the surface area of the piston. Thus, the “cost” of thisstroke-doubling approach is increasing the diameter of the actuatorcylinder by approximately 1.414. Also, it will be apparent to those ofreasonable skill that the technique is not limited to fluid-operatedactuators. Other types of actuators including electrical and manualactuators could also be employed. It is also reasonably apparent thatthe concept could be extended to have a motion multiplication of greaterthan two.

FIGS. 42A-42C illustrate the stroke-doubling feature in exemplarymanipulator system 10. In particular, FIGS. 42A-C show, the relativepositions of pulley carriage 140 and main arm assembly 500 with pistonrod 152 fully extended, retracted to the service position, and fullyretracted, respectively.

Having described a preferred embodiment of manipulator system 10,pneumatic control unit 700, which is a preferred embodiment of thepresent invention, will now be described with reference to FIGS. 43-57.FIG. 57 is a schematic diagram of the pneumatic control unit and isreferenced at various points throughout the following description.

FIGS. 43-53 provide partial interior views (portions of the interiorhave been removed for clarity) of pneumatics control unit 700.Pneumatics control unit 700 is configured for use with manipulatorsystem 10 described above, but may also be is utilized with othermanipulator systems and configurations. Control unit 700 includesmounting plate 710 and side plates 712 a and 712 b. Mounting plate 710and side plates 712 a and 712 b may be formed from a single piece ofsheet metal that is appropriately shaped and bent to orientate sideplates 712 a and 712 b at right angles to mounting plate 710. Variousair inlets 713 (e.g., a quick connect air inlet) are provided tofacilitate air distribution into the unit from working pressure airsupply 714 or control pressure air supply 715. Air regulator 720 issupported in the unit 700 and includes an inlet port 722 configured toreceive air from working pressure air supply 714 and an outlet port 723configured to provide a desired amount of pressure to mainfluid-operated actuator 150 (piping, tubing and the like are not shownin the figures for clarity). An exemplary regulator 720 provided is SMCModel IR 3020-F03. Air supply control valve 716 is provided in the flowpath between working pressure air supply 714 and regulator inlet port722 and controls the direction of flow of working air pressure toregulator 720. As will be described in greater detail hereinafter, uponreceipt of an up or down command, control pressure air will be directedto air supply control valve 716, whereupon, air supply control valve 716will be actuated to an open position such that work pressure air flowsto and through regulator 720. The amount of work pressure air that isregulated through regulator 720 is controlled by regulator adjustingshaft 725.

Regulator adjusting shaft 725 is pivoted or rotated to increase ordecrease the pressure output of regulator 720. As described hereinafter,input drive wheel 734 is driven via the pneumatic control unit toprovide automatic pivotal control of regulator adjusting shaft 725.Coupler 705 is attached to input drive wheel 734 and is coupled withregulator adjusting shaft 725 in a default condition, i.e. in anon-fluid energized condition. Pressure adjustment valve 707 controlsflow of control pressure air to coupler 705. Referring to FIG. 57,pressure adjustment valve 707 has a default closed position. Depressionof button 709 actuates pressure adjustment valve 707 to an open positionwherein control pressure air flows to and actuates coupler 705 to anuncoupled position. Regulator adjusting shaft 725 is free to be rotatedindependent of coupler 705 and input drive wheel 734. Engagement slot728 at the end of adjusting shaft 725 allows an operator to manuallyadjust the pressure output of regulator 720 by turning regulatoradjusting shaft 725 (e.g., using a hex, slotted, or Phillips driver)either clockwise or counterclockwise. Such manual adjustment isgenerally provided to allow the operator to set or adjust the pressureto achieve an equilibrium state of the manipulator system 10 (i.e. toprovide an air pressure approximately equal to, slightly less than, orslightly greater than the load on the piston 152).

As seen in FIG. 57, actuation of pressure adjustment valve 707 alsoprovides control pressure air to secondary brake release valve 774.Secondary brake release valve 774 is part of a brake control safetysystem which generally maintains pneumatic lock module 575, describedabove, in a locked condition. Pneumatic lock module 575 has a defaultnon-fluid energized locked position, i.e., if pneumatic lock module 575does not receive fluid from work pressure air supply 714, pneumatic lockmodule 575 remains locked such that main arm assembly 500 is preventingfrom moving vertically relative to the column 100. Primary brake releasevalve 772 and secondary brake release valve 774 are positioned betweenworking air pressure supply 714 and pneumatic lock module 575 and bothvalves 772 and 774 have a default closed position. Primary brake releasevalve 772 can only be actuated to an open position via safety valve 770.Safety valve 770 is a pressure actuated valve which opens when workingpressure at main fluid-operated actuator 150, as determined by line 822in FIG. 57, is above a threshold value. That is, if a sufficient workingpressure is not in the system, safety valve 770 will remain closed andwill not actuate primary brake release valve 772. Closed primary brakerelease valve 772 will prevent working air from reaching lock module 575and such will remain locked. Once the system has a sufficient workingpressure, safety valve 770 opens and control air pressure flows toprimary brake release valve 772 and thereby actuates primary brakerelease valve 772. An adjustment control 775 is provided to facilitatesetting of the desired minimum working pressure.

Secondary brake release valve 774 also has a default closed conditionsuch that even if system pressure is sufficient and primary brakerelease valve 772 is open, working pressure air is prevented fromreaching and releasing lock module 575 until secondary brake releasevalve 774 is actuated. Secondary brake release valve 774 is configuredto be actuated when a definite command to allow movement of main armassembly 500 is received. In the system illustrated in FIG. 57, thesecommands include either an up command or a down command, wherein controlpressure air flows through up/down control valve 730, or a manualadjustment command, wherein control pressure air flows through pressureadjustment valve 707. In these desired movement conditions, controlpressure air actuates secondary brake release valve 774 to an openposition such that lock module 575 is actuated and released. At allother times, secondary brake release valve 774 remains closed such thatlock module 575 remains in a locked condition.

In addition to manual adjustment of the position of regulator adjustingshaft 725, the control unit 700 is also configured to facilitate remotecontrol of the position of regulator adjusting shaft 725. Such remotecontrol will generally be used to is provide one of five operatingconditions, namely, neutral mode, up mode, down mode, manual up mode andmanual down mode, each described in more detail hereinafter.Pneumatically operated swivel actuator 731 is provided in control unit700 to remotely control the position of regulator adjusting shaft 725. Asuitable swivel actuator is the Swivel Module Type DSM available fromFesto Corporation, Hauppauge, N.Y. The output shaft (not shown) ofswivel actuator 731 extends through side plate 712 a and is connected tooutput drive wheel 732 which in turn is drivingly connected to an inputdrive wheel 734 associated with regulator adjusting shaft 725. In theillustrated embodiment, output drive wheel 732 and input drive wheel 734are both toothed and a tooth belt 735 extends therebetween. Other driveconnections, for example, a linkage assembly, may alternatively beutilized. Accordingly, pivoting of the output shaft of swivel actuator731 will cause a corresponding pivot or rotation of regulator adjustingshaft 725. As illustrated in FIG. 44, a gear ratio other than one-to-onebetween output drive wheel 732 and input drive wheel 734 may be utilizedto achieve a desired relationship between the movement of the outputshaft of swivel actuator 731 and the movement of regulator adjustingshaft 725.

Pivoting of the output shaft of swivel actuator 731 is pneumaticallycontrolled. Swivel actuator 731 includes up inlet 736 and down inlet 737which selectively receive air from control pressure air supply 715. Inthe present embodiment, the up inlet 736 and the down inlet 737 are eacha one direction, speed/flow controller. Up/down control valve 730 isfluidly positioned between control pressure air supply 715 and theinlets 736 and 737. In general operation, upon receipt of an up command,either up mode or manual up mode, up/down control valve 730 supplies airpressure to up inlet 736, and upon receipt of a down command, eitherdown mode or manual down mode, up/down control valve 730 supplies airpressure to down inlet 737. Control of up/down control valve 730 andassociated actuation of swivel actuator 731 will be described in greaterdetail hereinafter.

In the neutral mode, i.e. when regulator adjusting shaft 725 is in itspreset position with manipulator system 10 in an equilibrium state,swivel actuator 731 must correspondingly be in a default neutralposition wherein swivel actuator 731 does not pivot regulator adjustingshaft 725. This neutral mode condition is shown in FIGS. 43 and 44. Noair pressure is supplied to either inlet 736 or 737 and rotating stop738 on the inside surface of swivel actuator 731 is in a neutralposition, preferably equidistant from up/down stops 739 a/b. To ensureswivel actuator 731 is in this default position when the neutral mode isdesired, neutral mode block assembly 750 is provided. Neutral mode blockassembly 750 includes blocking member 752 which is is linearlydisplaceable relative to output drive wheel 732. Blocking member 752includes horizontal slot 753 with a tapered opening 754. Opening 754 isconfigured to guide alignment rollers 733 into horizontal slot 753 asblocking member 752 is moved linearly in the direction of arrow A inFIG. 44. Each alignment roller 733 is pivotally mounted on a front faceof output drive wheel 732. Alignment rollers 733 are configured onoutput drive wheel 732 such that when alignment rollers 733 are alignedhorizontally within horizontal slot 753, swivel actuator 731 is in thedefault neutral position. As such, linear movement of blocking member752 in direction A positively positions swivel actuator 731 in thedefault neutral position.

In the present embodiment, linear movement of blocking member 752 iscontrolled via pneumatic actuator 755 with piston rod 756 connected toblocking member 752. Extend inlet 757 and retract inlet 758 areconfigured to selectively receive air from control air pressure supply715 via block control valve 751. In the present embodiment, the extendinlet 757 and the retract inlet 758 are each a one direction, speed/flowcontroller. As shown in FIG. 57, block control valve 751 is such thatthe default flow of control air pressure from the valve is to extendinlet 757. As such, the default position of actuator 755 is with pistonrod 756, and thereby blocking member 752, extended. As furtherillustrated in FIG. 57, when either an up or down command is provided toup/down control valve 730 via valves 815 or 816 in remote control unit800, control air pressure is provided from up/down control valve 730 toan actuator of block control valve 751. Actuation of block control valve751 redirects the control air supply to the retract inlet 758 such thatblock member 752 is retracted. With blocking member 752 retracted, asshown in FIG. 45, alignment rollers 733 are clear of horizontal slot 753and output drive wheel 732 is free to pivot. In this preferredarrangement, blocking member 752 automatically moves to its retractedposition upon receipt of either an up or down command. Without an up ordown command, block control valve 751 is no longer actuated and blockingmember 752 automatically returns to the extended position.

The up mode, down mode, manual up mode and manual down modes will now bedescribed with reference to FIGS. 46-53. The up mode is illustrated inFIGS. 46, 46A and 47. Upon receipt of an “up” command from the remotecontroller (described hereinafter), block control valve 751 provides airpressure to retract inlet 758 of actuator 755 such that blocking member752 is moved to the retracted position (see FIG. 47). Up/down controlvalve 730 similarly provides air pressure to up inlet 736. Sincealignment rollers 733 are clear of horizontal slot 753, swivel actuator731 is free to rotate output drive wheel 732. As seen in FIG. 47, outputdrive wheel 732 is is rotated clockwise and thereby rotates input drivewheel 734 similarly such that regulator adjusting shaft 725 is rotatedclockwise (see position of inlet 780, the function of which is describedhereinafter, relative to its position in FIG. 44) to provide an increasein air pressure to main fluid-operated actuator 150. The amount ofrotation of regulator adjusting shaft 725, and thereby the amount of airpressure increase, is selected such that the pressure in mainfluid-operated actuator 150 will cause main arm assembly 500 to moveupward automatically. As described hereinafter, the rate of movement mayalso be selectively controlled. Referring to FIG. 46A, swivel actuator731 includes rotating stop 738 and up and down stops 739 a and b.Rotating stop 738 rotates in correspondence to rotation of the outputshaft of swivel actuator 731. Up stop 739 a is fixedly positioned alongthe arcuate path of rotating stop 738 to define a maximum range ofmotion of rotating stop 738, and thereby the output shaft of swivelactuator 731, in the up direction. As such, this up stop 739 a positiondefines a maximum amount of rotation of regulator adjustment shaft 725in the increased pressure direction. Upon release of the “up” command,up/down control valve 730 stops the supply of air pressure to up inlet736 and block control valve 751 automatically redirects air pressurefrom retract inlet 758 to extend inlet 757 such that blocking member 752is moved linearly toward the block position and swivel actuator 731 isautomatically moved to its default neutral position as shown in FIG. 44.

Referring to FIGS. 48, 48A and 49, the down mode operates in a similarfashion. Upon receipt of a “down” command from the remote controller,block control valve 751 provides air pressure to retract inlet 758 ofactuator 755 such that blocking member 752 is moved to the retractedposition (see FIG. 49). Up/down control valve 730 similarly provides airpressure to down inlet 737. Since alignment rollers 733 are clear ofhorizontal slot 753, swivel actuator 731 is free to rotate output drivewheel 732. As seen in FIG. 49, output drive wheel 732 is rotatedcounterclockwise and thereby rotates input drive wheel 734 similarlysuch that regulator adjusting shaft 725 is rotated counterclockwise (seethe relative position of inlet 780) to provide a decrease in airpressure to main fluid-operated actuator 150. The amount of rotation ofregulator adjusting shaft 725, and thereby the amount of air pressuredecrease, is selected such that the pressure in main fluid-operatedactuator 150 will allow main arm assembly 500 to move downwardautomatically. Referring to FIG. 48A, down stop 739 b is fixedlypositioned along the arcuate path of rotating stop 738 to define amaximum range of motion of rotating stop 738, and thereby the outputshaft of swivel actuator 731, in the down direction. As such, this downstop 739 b position defines a maximum amount of rotation of regulatoradjustment shaft 725 in the decreased pressure is direction. Uponrelease of the “down” command, up/down control valve 730 stops thesupply of air pressure to down inlet 737 and block control valve 751automatically redirects air pressure from retract inlet 758 to extendinlet 757 such that blocking member 752 is moved linearly toward theblock position and swivel actuator 731 is automatically moved to itsdefault neutral position as shown in FIG. 44.

In the up manual and down manual modes, only a slight pressure increaseor decrease is desired such that main arm assembly 500 does not move upor down automatically, but instead the slight pressure change assiststhe operator in moving main arm assembly 500 manually either up or down.As such, regulator adjustment shaft 725 requires less rotation than inup mode or down mode operation. To limit rotation of swivel actuator731, and thereby regulator adjustment shaft 725, in the manual modes,manual mode actuation assembly 760 is provided. Manual mode actuationassembly 760 includes linear actuators 762 and 764. Each linear actuator762, 764 is configured to selectively extend a corresponding stop rod763, 765 (see FIGS. 50 and 52, respectively) into the path of rotatingstop 738 between its neutral position and the corresponding up or downstop 739 a or b. Preferably, linear actuators 762 and 764 are pivotallyadjusted so that the manual stop positions may be adjusted to, and setat, a desired location. Upon selection of manual mode on remote controlunit 800 (see FIG. 55), manual valve 812 (see FIG. 56) provides air fromcontrol air pressure supply 715 to linear actuators 762 and 764, therebyextending stop rods 763 and 765. With both stop rods 763 and 765extended, the operator is ready to select either manual up or manualdown mode. If auto mode is thereafter desired, the knob 801 on remotecontrol unit is switched and manual valve 812 stops providing air tolinear actuators 762 and 764, whereby stop rods 763 and 765 retract.

Referring to FIGS. 50, 50A and 51, the manual up mode will be described.With the manual mode already selected, upon receipt of an “up” commandfrom the remote controller, block control valve 751 provides airpressure to retract inlet 758 of actuator 755 such that blocking member752 is moved to the retracted position (see FIG. 51). Up/down controlvalve 730 again provides air pressure to up inlet 736, however, contactof rotating stop 738 with stop rod 763 (see FIG. 50) limits rotation ofswivel actuator 731. As seen in FIG. 51, output drive wheel 732 isrotated clockwise, however, to a lesser extent than in the up mode asseen in FIG. 47. Similarly, input drive wheel 734, and thereby regulatoradjusting shaft 725, is rotated clockwise to a lesser extent (comparethe position of inlet 780 in FIG. 51 to that in FIG. 47). Such limitedrotation of regulator adjustment shaft 725 provides a slight increase inair pressure to main fluid-operated actuator 150 to assist an operatorin moving main arm assembly 500 upward. Upon release of the “up”command, up/down control valve 730 stops the supply of air pressure toup inlet 736 and block control valve 751 automatically redirects airpressure from retract inlet 758 to extend inlet 757 such that blockingmember 752 is moved linearly toward the block position and swivelactuator 731 is automatically moved to its default neutral position asshown in FIG. 44.

Referring to FIGS. 52, 52A and 53, the manual down mode will bedescribed. With the manual mode already selected, upon receipt of a“down” command from the remote controller, block control valve 751provides air pressure to retract inlet 758 of actuator 755 such thatblocking member 752 is moved to the retracted position (see FIG. 51).Up/down control valve 730 again provides air pressure to down inlet 737,however, contact of rotating stop 738 with stop rod 765 (see FIG. 52)limits rotation of swivel actuator 731. As seen in FIG. 53, output drivewheel 732 is rotated counterclockwise, however, to a lesser extent thanin the down mode as seen in FIG. 49. Similarly, input drive wheel 734,and thereby regulator adjusting shaft 725, is rotated counterclockwiseto a lesser extent (compare the position of inlet 780 in FIG. 53 to thatin FIG. 49). Such limited rotation of regulator adjustment shaft 725provides a slight decrease in air pressure to main fluid-operatedactuator 150 to assist an operator in moving main arm assembly 500downward. Upon release of the “down” command, up/down control valve 730stops the supply of air pressure to down inlet 737 and block controlvalve 751 automatically redirects air pressure from retract inlet 758 toextend inlet 757 such that blocking member 752 is moved linearly towardthe block position and swivel actuator 731 is automatically moved to itsdefault neutral position as shown in FIG. 44.

Having generally described the components of pneumatic control system700 its operation via an exemplary remote control unit 800 will bedescribed with reference to FIGS. 54-57. Referring to FIGS. 54 and 55,remote control unit 800 generally includes enclosed housing 802. Housing802 may be provided with handle 804 or the like to facilitate holdingthereof. As illustrated, various switches, knobs, buttons or the likeare acuatable outside of housing 802. In the present embodiment, remotecontrol unit 800 includes manual/auto knob 801; in/out switch 803;up/down switch 805 and slow/fast switch 807. More or fewer controls maybe provided. Remote control unit 800 is fluidly connected to pneumaticcontrol unit 700 via tubing or the like (not shown) with fluid enteringremote control unit 800 from control air pressure supply 715 and exitingto the various components as explained below.

Referring to FIG. 56, which illustrates remote control unit 800 with aportion of housing 802 removed, manual/auto knob 801 is associated withand controls manual valve 812. As explained above, manual valve 812provides fluid to linear actuators 762 and 764 upon selection of themanual mode.

In/out switch 803 is associated with and controls valves 813 and 814.Each of these valves 813, 814 is connected with in/out control valve790. Upon receipt of control pressure air from valve 813, in/out controlvalve 790 is actuated to provide air from working pressure air supply714 to inlet 791 at a near end of pneumatic cylinder 620 such thatpneumatic cylinder 620 is retracted and base plate 605 is moved “in”along the Z-axis 1004. Conversely, upon receipt of control pressure airfrom valve 814, in/out control valve 790 is actuated to provide air fromworking pressure air supply 714 to inlet 792 at a far end of pneumaticcylinder 620 such that pneumatic cylinder 620 is extended and base plate605 is moved “out” along the Z-axis 1004. In the present embodiment,inlets 791 and 792 are each a one direction, speed/flow controller.In/out switch 803 is biased to a neutral position wherein neither valve813, 814 is actuated such that pneumatic cylinder 620 is not moved ineither direction.

Up/down switch 805 is associated with and controls valves 815 and 816.Up/down switch 805 is biased to a neutral position wherein neither valve815 nor valve 816 is actuated. Each of these valves 815, 816 controlsfluid flow to up/down control valve 730. Upon receipt of fluid fromvalve 815, up/down control valve 730 provides air pressure to blockcontrol valve 751 which actuates block control valve 751 to provide airto retract inlet 758 to retract blocking member 752. Up/down controlvalve 730 also provides control pressure air to secondary brake releasevalve 774 such that pneumatic locking module 575 is released.Additionally, up/down control valve 730 provides control pressure air toair supply control valve 716 which is actuated to an open position inwhich working pressure air is provided to regulator 720. Finally,up/down control valve 730 provides air to up inlet 736 and control airpressure is supplied to actuate swivel actuator 731 in the up direction.These conditions remain as long as up/down switch 805 is maintaineddepressed to the up selection. Upon release of the switch 805, itreturns to a neutral position and flow through up/down control valve 730is terminated.

Similarly, upon receipt of fluid from valve 815, up/down control valve730 provides air pressure to block control valve 751 which actuatesblock control valve 751 to provide air to retract inlet 758 to retractblocking member 752. Up/down control valve 730 also provides controlpressure air to secondary brake release valve 774 such that pneumaticlocking module 575 is released. Additionally, up/down control valve 730provides control pressure air to air supply control valve 716 which isactuated to an open position in which working pressure air is providedto regulator 720. Finally, up/down control valve 730 provides air todown inlet 737 and control air pressure is supplied to actuate swivelactuator 731 in the down direction. These conditions remain as long asup/down switch 805 is maintained depressed to the down selection. Uponrelease of the switch 805, it returns to a neutral position and flowthrough up/down control valve 730 is terminated.

Slow/fast switch 807 is associated with and controls valves 817 and 818.Slow/fast or-gate 819 is associated with valves 817 and 818 and controlsthe flow of control pressure air based on the position of slow/fastswitch 807. Referring to FIG. 57, if slow/fast switch 807 is in the slowposition, control pressure air travels through valve 818 and slow/fastor-gate 819 directs the air only to the in/out valves 813, 814 andup/down valves 815, 816. The control pressure air reaching these valvesis controlled as explained above. Alternatively, if slow/fast switch 807is in the fast position, control pressure air travels through valve 817from which it travels to the in/out valves 813, 814 and up/down valves815, 816 for operation as described above, but also travels to fastcontrol valve 795. Fast control valve 795 is positioned in secondaryline 821 between regulator 720 and main fluid-operated actuator 150.Fast control valve 795 has a default closed position (the position whenin the slow mode) such that working pressure air can only flow fromregulator 720 to main fluid-operated actuator 150 over main supply line820. However, when slow/fast switch 807 is in the fast position andcontrol pressure air travels through valve 817 and actuates fast controlvalve 795, fast control valve 795 opens, thereby opening secondary line821. The amount of fluid to main fluid-operated actuator 150 is nowincreased by the flow rate through secondary line 821, therebyincreasing the operating rate of main fluid-operated actuator 150.

An alternative exemplary pneumatic control unit 2600 will be describedwith reference to FIGS. 59-61. The pneumatic control unit 2600 isconfigured to control the pressure and flow of fluid to fluid-operatedactuator 150 to control the up and down motion of the piston rod 152 aswell as its static and compliant behavior. Additional in and out androtational control are also provided as described below. A pneumaticschematic diagram of the control unit 2600 is illustrated in FIG. 59while an exemplary remote control unit 2700 is illustrated in FIGS. 60and 61. Common elements are numbered alike in the figures. While thecontrol unit 2600 is described herein as a pneumatic system utilizingair as the operating fluid, the invention system is not limited to suchand other fluids, for example, oil, may be utilized.

In the present embodiment, the fluid-operated actuator 150 is a doubleacting cylinder which is vented to atmosphere at port 2601 on one sideof the piston 145 and connected to a pneumatic feed line 2603 on theopposite side of the piston 45. A spring biased check valve 2602 isprovided in feed line 2603 and is configured to close upon loss of pilotpressure in the system to prevent falling of the piston rod 152. Apiloted, biased pressure regulator 2604 is positioned along the feedline 2603 and is configured to control the pressure (and consequentlythe rate of flow) of the fluid delivered to the fluid-operated actuator150. The pressure regulator 2604 receives pressurized fluid from apressure source 2650 along pressure feed line 2605. A pressure regulator2648 is provided along the pressure feed line 2605 to regulate the fluidpressure to a desired pressure. Pressure regulator 2648 also includes afilter 2649 to clean the air as it enters the system.

Biased pressure regulator 2604 includes a biasing member, for example, acontrol knob, to allow mechanical adjustment of the pressure and fluidflow through regulator 2604 to initialize the system. The biasing membercan also be subsequently adjusted to reset the system as necessary. Thebiasing member and pilot input port can be manipulated such that thefluid pressure passing through the biased pressure regulator 2604provides an upwards force on piston 145 that is substantially equal tothe downward force applied by the load on the piston rod 152. Byequalizing such pressure, the pressure on the piston rod 152 is balancedsuch that the test head 490, is in a static or substantially weightlessstate. While in a weightless state, the heavy test head 490 may bemanually positioned to dock (i.e., mate or engage) the test electronicsof the heavy test head 490 with the IC under test disposed on theperipheral testing apparatus. As described in more detail inWO/05015245A2, due to friction and the breakaway force associated withpiston 45, the upwards and downwards pressures acting on piston 45 donot need to be exactly equal to maintain a static position. As isfurther described in WO/05015245A2, the pressure provided by the systemmay be slightly adjusted higher or lower for added system functionalityand capabilities.

A plunger throttle assembly 2680 is provided in the pneumatic controlunit 2600 to allow an operator to control upward and downward movementof the piston rod 152. While a plunger throttle assembly is shown anddescribed, other types of pneumatic components capable of modulatingpressure (such as directional control valves) may be utilized. Theplunger throttle assembly 2680 includes a plunger actuated pressureregulator 2682 which receives input pressure from the pressure source2650 via line 2681 and supplies a supplemental pressure to the biasedpressure regulator 2604 when enabled.

To prevent inadvertent movement of the test head 490, the pneumaticcontrol unit 2600 includes an enablement valve 2630 which must beactuated before the lock module 575 is released to allow vertical motionand before the plunger throttle assembly 2680 is fluidly connected tothe biased pressure regulator 2604. When the actuator 2631 of enablementvalve 2630 is not depressed, no air flows through normally open systemcontrol valve 2633 and lock control valve 2632 remains closed, thus noair flows to the vertical lock module 575 or check valve 2602 and thepiston rod 152 is restricted from moving. Also when enablement valve2630 is not actuated, no air flows through normally open system controlvalve 2633 and regulator control valve 2617 remains in its initialposition which allows regulated pressure from regulator 2614 to flow tothe pilot input port of the biased pressure regulator 2604. Theregulated pressure of regulator 2614 will always remain as a constantpressure P1. Pressure output P1 of regulator 2614 plus the bias controlof the biased pressure regulator 2604 is sufficient to balance the loadplaced on the piston rod 152. The output of biased pressure regulator2604 goes to the pilot input of volume booster regulator 2618. Thevolume booster regulator 2618 outputs the same pressure as received atthe pilot input but at a higher flow capacity. Thus the pilot input ofvolume booster regulator 2618 is the same pressure as the output ofvolume booster regulator 2618. Check valve 2602 is between the regulator2618 and the actuator 150 for safety to prevent sudden out rush ofpressure from the actuator 150.

Pressing actuator 2631 allows air to flow through normally open systemcontrol valve 2633 and then to the pilot actuator of lock control valve2632 which allows the lock module 575 and check valve 2602 to open,assuming the safety sensing valve 2629 is on and has opened lock safetyvalve 2628. Pressing actuator 2631 also allows air to flow throughnormally open system control valve 2633 and then to the pilot actuatorof regulator control valve 2617 which then allows regulated pressurefrom the plunger actuated pressure regulator 2682 to flow to the pilotinput port of biased pressure regulator 2604.

The present plunger actuated pressure regulator 2682 is continuouslyvariable over a range from atmospheric pressure to a positive pressurevia a plunger 2684. The plunger throttle assembly 2680 includes a handle2686 or the like configured to engage the plunger 2684. A spring 2688 orthe like biases the handle 2686 against the plunger 2684 so that theplunger 2684 is moved to a neutral position wherein a desired preloadpressure flows through the regulator 2682. The preload pressure in theneutral position is the same pressure P1. The preload pressure can beany desired pressure, for example, 10 psi, to provide a sufficient rangeof increase or decrease in the set pressure. Movement of the handle 2686toward the plunger 2684 causes an increased pressure more than thepreload pressure to flow through the plunger actuated pressure regulator2682 to the pilot control of the pressure regulator 2604. Movement ofthe handle 2686 away from the plunger 2684 causes a decreased pressureless than the preload pressure to flow through the plunger actuatedpressure regulator 2682 to the pilot control of the pressure regulator2604. The control of increased or decreased pressure is continuouslyvariable over the range of motion of the handle 2686 and provides theoperator a means to control the vertical motion.

As set forth above, in the present embodiment, pneumatic control unit2600 is also configured to control in and out movement and rotationalmovement. Forward movement of the carriage is controlled by a forwardcontrol valve 2640 with an actuator 2641. Forward control valve 2640receives input pressure over line 2635 which is output from enablementvalve 2630. As such, enablement valve 2630 must be actuated to allowforward control. Pressing of the actuator 2641 when the enablement valve2630 is actuated allows fluid to flow to the pilot control of normallyclosed forward actuation valve 2642. Forward actuation valve 2642 isopened and fluid pressure from line 2605 is provided to the horizontalmotion control cylinder 6. In the present embodiment, the cylinder 6 isthat of the embodiment shown and described with respect to FIGS. 17-32A,however, other configurations may also be utilized.

The control unit 2600 is also configured to control rotational movementvia a twist motor 2620. Rotational movement is controlled by a clockwisecontrol valve 2621 with an actuator 2622 and counterclockwise controlvalve 2623 with an actuator 2624. Both control valves 2621 and 2623receive input pressure over line 2635 which is output from enablementvalve 2630. As such, enablement valve 2630 must be actuated to allowrotational control. Pressing of the actuator 2622 when the enablementvalve 2630 is actuated allows fluid to flow to the clockwise pilotcontrol of three-way rotational actuation valve 2626. Rotationalactuation valve 2626 is opened and fluid pressure from line 2605 isprovided to the clockwise input of twist motor 2620. Alternatively,pressing of the actuator 2624 when the enablement valve 2630 is actuatedallows fluid to flow to the counterclockwise pilot control of three-wayrotational actuation valve 2626. Rotational actuation valve 2626 isopened and fluid pressure from line 2605 is provided to thecounterclockwise input of twist motor 2620. As an additional safetyfeature, if either or both valves 2621, 2623 are actuated, the output ofshuttle valve 2628 switches the position of normally open system controlvalve 2633, thus not allowing air to switch valves 2617 and 2632 whichkeep the vertical cylinder fixed during rotational movement.

Referring to FIGS. 62-68, an alternative manipulator system will bedescribed. The manipulator system of the present embodiment is similarto the previous embodiment and components and items which aresubstantially the same will use the same reference numbers as theprevious description while components and items which are similar buthave changed will use the previous reference number with an “A” or “Alt”suffix appended to it.

As shown in FIGS. 62 and 64, lift carriage 140A of column assembly 100Aincludes end cap 128A at the protruding end of lift carriage 140A. Endcap 128A replaces the lift arm 128 of the previous embodiment. End cap128A has a reduced width compared to lift arm 128 and does not requirelinear bearings 125 a and 125 b, as in the previous embodiment, whichmay result in less friction with respect to vertical motion. Such may bedesirable in situations requiring compliant motion of the test head inresponse to external forces. End cap 128A is provided primarily forsafety reasons; accordingly, end cap 128A may be fabricated from areasonably heavy gauged sheet metal or other suitable material for suchpurpose. As shown in FIG. 64, lift carriage 140A includes pulleys 142a-142 d and generally operates in a similar manner as lift carriage 140shown and described with reference to FIG. 39.

With the lift arm omitted, a support bracket may be included, as shownin FIG. 63, to minimize tipping of fluid-operated actuator 150. In thepresent embodiment, the support bracket comprises horizontal member 195which is attached to front structural member 118 of column 100A viaattachment member 196. Horizontal member 195 includes circular opening193 which is configured to receive boss 153 (see FIG. 38) on the upperend of fluid-operated actuator 150. Boss 153 fits within circularopening 193 and thereby prevents fluid-operated actuator 150 fromtipping in unloaded circumstances as described above.

Referring to FIGS. 58, 63, 64, 67 and 68, a speed control option whichis incorporated into the present embodiment will be described. While thespeed control option is described with reference to this embodiment, itis not limited to such and may be used with other embodiments of themanipulator system. Referring to FIGS. 63 and 64, valve actuator plate180 is attached to lift carriage 140A. In the current embodiment, valveactuator plate 180 is attached with two screws 181 that are passedthrough slotted holes 182, which provides a means for adjustment,however, other connection means may be utilized. The opposed ends 183 a,183 b of the exemplary actuator plate 180 are tapered.

Referring to FIGS. 67 and 68, roller-actuated 3/2 (3 ports/2 positions)valve 185 is provided on the interior of column assembly 100A.Roller-actuated valve 185 includes roller 186 which is movable between afirst, non-contacted position in which valve 185 is not actuated and asecond, depressed position in which valve 185 is actuated.Roller-actuated valve 185 is optional and is used with valve actuatorplate 180. The use of valve actuator plate 180 and roller-actuated valve185 is optional, depending upon application requirements. Valve-actuatorplate 180 and roller-actuated valve 185 may also be optionally used inconjunction with the earlier described column 100 and lift carriage 140of FIG. 39. Furthermore, while the present embodiment describes a fluidvalve 185 acting as a switch, such valve may be replaced with anelectrical switch or the like.

In FIG. 68, lift carriage 140A has been raised to it uppermost position.In this position, the valve-actuator plate 180 presses on roller 186 ofroller-actuated valve 185, and, accordingly, valve 185 is switched intoits second, actuated position. When lift carriage 140A is lowered fromthis position, roller 186 will first roll along actuator plate 180 for adistance D 179, remaining depressed and maintaining valve 185 in itsactuated position. As carriage 140A is lowered further, roller 186 rollsoff actuator plate 180 at tapered end 183 a. Roller 186 then returns toits non-depressed position, and valve 185 switches to its first,non-actuated state. Conversely, when lift carriage 140A is moved in theopposite direction from the non-actuated state, as lift carriage 140A israised, roller 186 eventually comes into initial engagement with taperedend 183 a of actuator plate 180. As lift carriage 140A is furtherraised, roller 186 rolls onto actuator plate 180 and is depressed,thereby causing valve 185 to switch to its second, actuated state. Valve185 remains in its actuated state as lift carriage 140A is raised to itsuppermost position. Thus, the interaction of roller-actuated valve 185and actuator plate 180 provides a signal indicating that lift carriage140A is within a distance D 179 of its uppermost region of travel. Thissignal may be used by the fluid control signal to aid in the control ofvertical motion of the load.

Again, the use of valve 185 and actuator plate 180 is optional anddepends upon the circumstances of specific applications. Furthermore,although the arrangement just described is configured to detect motionnear the upper (highest) limit of travel, valve 185 may be positionedelsewhere along the column and used to signal travel in other regions.For example, by locating a valve near the upper end of fluid-actuatedcylinder 150, it would be possible to signal that the load is in thelower end of its range of travel. Also, valve 185 may be located at anintermediate position to indicate that the load is in an intermediaterange of vertical travel that may be of interest, for example, in thevicinity of the service position or possibly in the vicinity of adocking position. Alternatively, multiple valves 185 may be provided atdifferent positions to signal different positions of the lift carriage140A.

Referring to FIG. 58, operation of the speed control option of thepresent embodiment will be described. Roller-actuated valve 185 receivescontrol pressure air from control pressure air supply 715 and isconfigured to selectively provide control pressure air to supplementalair valve 840. Supplemental air valve 840 is an air actuated valve thatis positioned in a supplemental line 823 between regulator 720 andfluid-operated actuator 150. Supplemental valve 840 has a normallyclosed position such that working pressure air does not flowtherethrough, but instead flows to fluid-operated actuator 150 in thenormal course as described above with reference to FIG. 57. In thefirst, non-actuated state, valve 185 is in a closed condition such thatcontrol pressure air does not pass thereby and supplemental valve 840remains in the closed position. Upon movement of lift carriage 140A tothe upper range of movement, i.e., within the range 179, roller 186 isdepressed and valve 185 is actuated. Control pressure air passes throughvalve 185 and actuates supplemental air valve 840. Supplemental airvalve 840 is opened and provides a supplemental flow path 823 betweenregulator 720 and fluid-operated actuator 150, thereby increasing theflow rate to fluid-operated actuator 150. In the present embodiment, theincreased flow rate helps to maintain a constant motion of thefluid-operated actuator 150 as it extends to its outer limit. Otherconfigurations may also be provided.

Although the present invention has been described primarily in terms ofa test head attachment unit situated on a column where pneumatics areused to provide vertical motion in a substantially weightless condition,the novel concepts described herein may also be used with other types ofmanipulators, including, but not limited to counterbalancedmanipulators. The invention does not depend upon the means of providingvertical support and motion.

Various aspects of the present invention have been described usingpneumatic systems operating on compressible fluids. As used herein, theterm “fluid” refers to a broad category of fluids including both gasesand liquids.

As used herein, the term “compliant mechanism” refers to a mechanism(e.g., a spring, a pneumatic actuator, etc.) that at least partiallyprovides a force for supporting a load in a substantially weightlesscondition in a direction or about an axis.

Although the present invention has primarily been described in terms ofa test head for testing integrated circuits, it is not limited thereto.Various aspects of the invention may be applied to any of a number ofdifferent loads, particularly heavy loads that require precisemanipulation and/or positioning.

Although the invention is illustrated and described herein withreference to specific embodiments, the invention is not intended to belimited to the details shown. Rather, various modifications may be madein the details within the scope and range of equivalents of the claimsand without departing from the invention.

What is claimed:
 1. A test head manipulator system comprising: a basestructure; a main arm unit configured to support a test head and to bemoved along a first axis relative to the base structure; an actuatorhaving a range of motion of L along an axis parallel to the first axis;and an enhancement mechanism positioned between the main arm unit andthe actuator and configured such that movement of the actuator a firstdistance causes the main arm unit to move along the first axis a seconddistance that is greater than the first distance.
 2. The test headmanipulator system according to claim 1 wherein the enhancementmechanism includes a lift carriage which is associated with and moveswith the actuator.
 3. The test head manipulator system according toclaim 2 wherein the enhancement mechanism further includes a strap whichis looped about the lift carriage and which has a first end securedrelative to the base structure and a second end secured relative to themain arm unit.
 4. The test head manipulator system according to claim 3wherein the lift carriage includes at least one pulley which supportsthe strap.
 5. The test head manipulator system according to claim 2wherein the lift carriage includes a lift arm which travels along thefirst axis and guides the lift carriage.
 6. The test head manipulatorsystem according to claim 1 wherein the second distance is at leasttwice the first distance.
 7. A fluid control system for controlling atest head manipulator system which includes a main fluid actuatorconfigured to vertically position a test head relative to a basestructure, the fluid control system including: a regulator configured tocontrollably provide an output pressure to the main fluid actuator; asecond fluidly controlled actuator configured to adjust the regulator tomodify the output pressure provided to the main fluid actuator, thesecond actuator configured to be positively positioned in a plurality ofoperating modes, each operating mode causing the regulator to provide adifferent output pressure to the main fluid actuator.
 8. The fluidcontrol system according to claim 7 wherein the second actuator isconfigured to be positively positioned in at least three operatingmodes.
 9. The fluid control system according to claim 7 wherein thesecond actuator is configured to be positively positioned in at leastfour operating modes.
 10. The fluid control system according to claim 9wherein the second actuator is configured to be positively positioned ina fifth operating mode which is a neutral mode.
 11. The fluid controlsystem according to claim 7 further comprising a fluidly actuated safetylock configured to lock the vertical position of the test head relativeto the base structure if a fluid pressure in the main fluid actuator isbelow a threshold value.
 12. The fluid control system according to claim7 further comprising a fluid rate control including at least onedirectional control valve which is fluidly or mechanically actuablebetween an open and closed position to increase or decrease,respectively, a rate of fluid flow to the main fluid actuator.
 13. Thefluid control system according to claim 7 wherein one of the operatingmodes is a manual up mode wherein the output pressure is slightlygreater than the pressure required to balance the load such that theamount of external force required to move the load upwards is reducedbut the output pressure is not enough for the load to move unassisted.14. The fluid control system according to claim 7 wherein one of theoperating modes is a manual down mode wherein the output pressure isslightly less than the pressure required to balance the load such thatthe amount of external force required to move the load downwards isreduced but the output pressure is not enough for the load to moveunassisted.
 15. The fluid control system according to claim 7 whereinone of the operating modes is an up mode wherein the output pressure isgreater than the pressure required to balance the load such that theload moves upward unassisted.
 16. The fluid control system according toclaim 7 wherein one of the operating modes is a down mode wherein theoutput pressure is less than the pressure required to balance the loadsuch that the load moves downward unassisted.
 17. A fluid control systemfor controlling a test head manipulator system which includes a mainfluid actuator configured to vertically position a test head relative toa base structure, the fluid control system including: a regulatorconfigured to controllably provide an output pressure to the main fluidactuator at a first given rate along a first flow path; a supplementalflow path extending between the regulator and the main fluid actuator; asupplemental valve positioned along the supplemental flow path andconfigured to control flow therealong; and a controller configured todetermine a vertical extension of the main fluid actuator and controlthe supplemental valve when the main fluid actuator is verticallyextended within a given range.
 18. The fluid control system of claim 17further comprising at least a second supplemental flow path with acorresponding supplemental valve, and wherein the controller isconfigured to determine the vertical extension of the main fluidactuator over multiple ranges and control a respective supplementalvalve in response to a determined range.
 19. A test head manipulatorsystem comprising: a coupling unit configured to support a test head forrotation about a given axis; a rotation unit configured to controllablyprovide a rotational output; a drive belt extending between saidrotation unit and said coupling unit and configured to transmit saidrotational output to said coupling unit; and at least one idler biasedinto engagement with the drive belt and moveable over a given path suchthat when an external force is applied to said coupling unit, said idlermaintains a desired tension on said drive belt.
 20. The test headmanipulator system according to claim 19 wherein the at least one idleris configured such that the coupling unit returns to an originalposition once the external force is released.
 21. The test headmanipulator system according to claim 19 comprising at least two idlers,with each idler providing a biasing force to the drive belt.
 22. Thetest head manipulator system according to claim 21 wherein the biasingforces of the at least two idlers are distinct.
 23. The test headmanipulator system according to claim 19 wherein the at least one idleris spring biased.
 24. The test head manipulator system according toclaim 19 wherein the at least one idler is fluidly biased.
 25. The testhead manipulator system according to claim 24 wherein the fluid bias isadjustable.
 26. The test head manipulator system according to claim 25wherein the fluid bias is adjusted based on an operation condition ofthe test head manipulator system.
 27. The test head manipulator systemaccording to claim 26 wherein the fluid bias is increased when the testhead manipulator system is driving the position of the test head and thefluid bias is lower the when the test head is not being driven.
 28. Thetest head manipulator system according to claim 19 wherein the couplingunit is rotationally compliant throughout its entire range of motion.29. The test head manipulator system according to claim 19 wherein thecoupling unit is configured to prevent back-driving thereof.
 30. Thetest head manipulator system according to claim 19 wherein the givenaxis is horizontal.
 31. The test head manipulator system according toclaim 30 wherein the load may be substantially balanced with respect torotation about the given axis.
 32. A linear actuator assembly for movinga carriage relative to a base plate, the linear actuator assemblycomprising: a fluid cylinder connected at one end to the carriage; abrake shoe connected to a piston rod extending from an opposite end ofthe fluid cylinder; at least one ramp block defining a ramped slot, theat least one ramp block connected to the carriage for linear motiontherealong; and a pin member extending from the brake shoe and receivedin the ramped slot such that movement of the cylinder causes the pinmember to move along the ramped slot and thereby move the brake shoeinto and out of engagement with the base plate.
 33. The linear actuatorassembly according to claim 32 wherein movement of the cylinder when thebrake shoe is engaged with the base plate causes the carriage to moverelative to the base plate.
 34. The linear actuator assembly accordingto claim 32 wherein the cylinder is moveable over a given stroke whichdefines an operation cycle.
 35. The linear actuator assembly accordingto claim 34 wherein the operation cycle may be performed multiple times.36. The linear actuator assembly according to claim 34 wherein theoperation cycle may be performed independent of the relative position ofthe carriage to the base plate.
 37. The linear actuator assemblyaccording to claim 34 wherein each operation cycle causes the carriageto move a predetermined distance relative to the base plate.
 38. Thelinear actuator assembly according to claim 32 wherein a drive force ofthe cylinder is maintained below a desired threshold.
 39. A loadpositioning system for translating a load along an axis of translation,said load positioning system comprising: a support coupled to said load;a fluidly operated piston configured to drive said support along saidaxis of translation; a regulator unit configured to control a pressureof a primary fluid delivered to said fluidly operated piston, saidregulator unit receiving a first supply of fluid and a second supply offluid; and a control unit configured to control a pressure of saidsecond supply of fluid to said regulator, wherein increasing thepressure of said second supply of fluid causes said pressure of saidprimary fluid to be increased and said support to move in a firstdirection, decreasing the pressure of said second supply of fluid causessaid pressure of said primary fluid to be decreased and said support tomove in the opposite direction, and maintaining the pressure of saidsecond supply of fluid at a constant pressure substantially maintainsthe position of said support along said axis of translation.
 40. Theload positioning system according to claim 39 further comprising acontrol valve configured to prevent operation of the control unit unlessthe control valve is actuated.
 41. The load positioning system accordingto claim 39 wherein the control unit is further configured to control aflow of fluid to a linear actuator assembly for moving a carriage uponwhich said piston is supported relative to a base plate.
 42. The loadpositioning system according to claim 41 wherein the linear actuatorassembly comprises: a fluid cylinder connected at one end to thecarriage; a brake shoe connected to a piston rod extending from anopposite end of the fluid cylinder; at least one ramp block defining aramped slot, the at least one ramp block connected to the carriage forlinear motion therealong; and a pin member extending from the brake shoeand received in the ramped slot such that movement of the cylindercauses the pin member to move along the ramped slot and thereby move thebrake shoe into and out of engagement with the base plate.
 43. The loadpositioning system according to claim 42 wherein the control unitcontrols the flow of fluid to the fluid cylinder.
 44. The loadpositioning system according to claim 39 wherein the control unit isfurther configured to control a flow of fluid to a rotational actuatorfor rotationally adjusting the orientation of said support.
 45. A systemfor positioning a load comprising: a support structure; a main arm unitconfigured to support said load and to be moved along a first axisrelative to the support structure; and a damper positioned between thesupport structure and said main arm unit.
 46. The system according toclaim 45 wherein the load is a test head.
 47. The system according toclaim 45 wherein the first axis is vertical.
 48. The system according toclaim 45 wherein the damper is a fluid damper.
 49. The system accordingto claim 45 wherein the load is movable along the first axis by a fluidoperated actuator.
 50. The system according to claim 45 wherein thedamper is configured to minimize sudden motion of the load.
 51. Thesystem according to claim 45 wherein one of the support structure andthe main arm unit includes a rack and the other includes a pinionsupported on a shaft, and wherein the damper engages the shaft.